Science.gov

Sample records for global n-acetyl aspartate

  1. Medial temporal N-acetyl aspartate in pediatric major depression

    PubMed Central

    MacMaster, Frank P.; Moore, Gregory J; Russell, Aileen; Mirza, Yousha; Taormina, S. Preeya; Buhagiar, Christian; Rosenberg, David R.

    2008-01-01

    The medial temporal cortex (MTC) has been implicated in the pathogenesis of pediatric major depressive disorder (MDD). Eleven MDD-case control pairs underwent proton magnetic resonance spectroscopic imaging. N-acetyl-aspartate was lower in left MTC (27%) in MDD patients versus controls. Lower N-acetyl-aspartate concentrations in MDD patients may reflect reduced neuronal viability. PMID:18703320

  2. Medial temporal N-acetyl-aspartate in pediatric major depression.

    PubMed

    MacMaster, Frank P; Moore, Gregory J; Russell, Aileen; Mirza, Yousha; Taormina, S Preeya; Buhagiar, Christian; Rosenberg, David R

    2008-10-30

    The medial temporal cortex (MTC) has been implicated in the pathogenesis of pediatric major depressive disorder (MDD). Eleven MDD case-control pairs underwent proton magnetic resonance spectroscopic imaging. N-acetyl-aspartate was lower in the left MTC (27%) in MDD patients versus controls. Lower N-acetyl-aspartate concentrations in MDD patients may reflect reduced neuronal viability. PMID:18703320

  3. In vivo differentiation of N-acetyl aspartyl glutamate from N-acetyl aspartate at 3 Tesla.

    PubMed

    Edden, Richard A E; Pomper, Martin G; Barker, Peter B

    2007-06-01

    A method is described that allows the in vivo differentiation of N-acetyl aspartate (NAA) from N-acetyl aspartyl glutamate (NAAG) by in vivo MR spectroscopy (MRS) at 3 Tesla (3T). The method, which is based on MEGA-point-resolved spectroscopy (PRESS) editing, selectively targets the aspartyl spin system of one species while deliberately removing the other species from the spectrum. This allows quantitative measurements of NAA and NAAG without the need for fitting of unresolved peaks. White matter concentrations of NAA (6.7 +/- 0.3 mM) and NAAG (2.2 +/- 0.3 mM) were measured in 10 healthy volunteers to demonstrate the method. PMID:17534922

  4. The effect of N-acetyl-aspartyl-glutamate and N-acetyl-aspartate on white matter oligodendrocytes.

    PubMed

    Kolodziejczyk, Karolina; Hamilton, Nicola B; Wade, Anna; Káradóttir, Ragnhildur; Attwell, David

    2009-06-01

    Elevations of the levels of N-acetyl-aspartyl-glutamate (NAAG) and N-acetyl-aspartate (NAA) are associated with myelin loss in the leucodystrophies Canavan's disease and Pelizaeus-Merzbacher-like disease. NAAG and NAA can activate and antagonize neuronal N-methyl-D-aspartate (NMDA) receptors, and also act on group II metabotropic glutamate receptors. Oligodendrocytes and their precursors have recently been shown to express NMDA receptors, and activation of these receptors in ischaemia leads to the death of oligodendrocyte precursors and the loss of myelin. This raises the possibility that the failure to develop myelin, or demyelination, occurring in the leucodystrophies could reflect an action of NAAG or NAA on oligodendrocyte NMDA receptors. However, since the putative subunit composition of NMDA receptors on oligodendrocytes differs from that of neuronal NMDA receptors, the effects of NAAG and NAA on them are unknown. We show that NAAG, but not NAA, evokes an inward membrane current in cerebellar white matter oligodendrocytes, which is reduced by NMDA receptor block (but not by block of metabotropic glutamate receptors). The size of the current evoked by NAAG, relative to that evoked by NMDA, was much smaller in oligodendrocytes than in neurons, and NAAG induced a rise in [Ca(2+)](i) in neurons but not in oligodendrocytes. These differences in the effect of NAAG on oligodendrocytes and neurons may reflect the aforementioned difference in receptor subunit composition. In addition, as a major part of the response in oligodendrocytes was blocked by tetrodotoxin (TTX), much of the NAAG-evoked current in oligodendrocytes is a secondary consequence of activating neuronal NMDA receptors. Six hours exposure to 1 mM NAAG did not lead to the death of cells in the white matter. We conclude that an action of NAAG on oligodendrocyte NMDA receptors is unlikely to be a major contributor to white matter damage in the leucodystrophies. PMID:19383832

  5. Measuring N-acetyl aspartate synthesis in vivo using proton magnetic resonance spectroscopy

    PubMed Central

    Xu, Su; Yang, Jehoon; Shen, Jun

    2008-01-01

    N-acetyl aspartate (NAA) is an important marker of neuronal function and viability that can be measured using magnetic resonance spectroscopy (MRS). In this paper, we proposed a method to measure NAA synthesis using proton MRS with infusion of uniformly 13C-labeled glucose, and demonstrated its feasibility in an in vivo study of the rat brain. The rate of 13C-label incorporation into the acetyl group of NAA was measured using a localized, long echo-time proton MRS method. Signals from the 13C satellites of the main NAA methyl protons at 2.02 ppm were continuously monitored for 10 hours. Quantification of the data based on a linear kinetic model showed that NAA synthesis rate in isoflurane-anesthetized rats was 0.19 ± 0.02 µmol/g/h (mean ± standard deviation, n = 12). PMID:18486230

  6. Lithium citrate reduces excessive intra-cerebral N-acetyl aspartate in Canavan disease.

    PubMed

    Assadi, Mitra; Janson, Christopher; Wang, Dah-Jyuu; Goldfarb, Olga; Suri, Neeti; Bilaniuk, Larissa; Leone, Paola

    2010-07-01

    Our group has previously reported the first clinical application of lithium in a child affected by Canavan disease. In this study, we aimed to assess the effects of lithium on N-acetyl aspartate (NAA) as well as other end points in a larger cohort. Six patients with clinical, laboratory and genetic confirmation of Canavan disease were recruited and underwent treatment with lithium. The battery of safety and efficacy testing performed before and after sixty days of treatment included Gross Motor Function Testing (GMFM), Magnetic Resonance Imaging (MRI) Proton Magnetic Spectroscopy (H-MRS) as well as blood work. The medication was safe without any clinical or laboratory evidence for toxicity. Parental reports indicated improvement in alertness and social interactions. GMFM did not show statistically significant improvement in motor development. H-MRS documented an overall drop in NAA which was statistically significant in the basal ganglia. T1 measurements recorded on MRI studies suggested a mild improvement in myelination in the frontal white matter after treatment. Diffusion Tensor Imaging was available in two patients and suggested micro-structural improvement in the corpus callosum. The results suggest that lithium administration may be beneficial in patients with Canavan disease. PMID:20034825

  7. The relationship between Gulf war illness, brain N-acetyl aspartate and post-traumatic stress disorder

    PubMed Central

    Weiner, Michael W.; Meyerhoff, Dieter J.; Neylan, Thomas C.; Hlavin, Jennifer; Ramage, Erin R.; McCoy, Daniel; Studholme, Colin; Cardenas, Valerie; Marmar, Charles; Truran, Diana; Chu, Philip W.; Kornak, John; Furlong, Clement E.; McCarthy, Charles

    2012-01-01

    A previous study (1) suggested that individuals with Gulf War Illness (GWI) had reduced quantities of the neuronal marker N-acetyl aspartate (NAA) in the basal ganglia and pons. This study aimed to determine whether NAA is reduced in these regions and to investigate correlations with other possible causes of GWI, such as psychological response to stress in a large cohort of Gulf war veterans. Individuals underwent tests to determine their physical and psychological health and to identify veterans with (n=81) and without (n=97) GWI. When concentrations of NAA and ratios of NAA to creatine- and choline-containing metabolites were measured in the basal ganglia and pons, no significant differences were found between veterans with or without GWI, suggesting that GWI is not associated with reduced NAA in these regions. Veterans with GWI had significantly higher rates of Post Traumatic Stress Disorder (PTSD), supporting the idea that GWI symptoms are stress-related. PMID:21882779

  8. Lower "N"-Acetyl-Aspartate Levels in Prefrontal Cortices in Pediatric Bipolar Disorder: A (Superscript 1]H Magnetic Resonance Spectroscopy Study

    ERIC Educational Resources Information Center

    Caetano, Sheila C.; Olvera, Rene L.; Hatch, John P.; Sanches, Marsal; Chen, Hua Hsuan; Nicoletti, Mark; Stanley, Jeffrey A.; Fonseca, Manoela; Hunter, Kristina; Lafer, Beny; Pliszka, Steven R.; Soares, Jair C.

    2011-01-01

    Objective: The few studies applying single-voxel [superscript 1]H spectroscopy in children and adolescents with bipolar disorder (BD) have reported low "N"-acetyl-aspartate (NAA) levels in the dorsolateral prefrontal cortex (DLPFC), and high myo-inositol/phosphocreatine plus creatine (PCr+Cr) ratios in the anterior cingulate. The aim of this study…

  9. Magnetic resonance spectroscopy reveals oral Lactobacillus promotion of increases in brain GABA, N-acetyl aspartate and glutamate.

    PubMed

    Janik, Rafal; Thomason, Lynsie A M; Stanisz, Andrew M; Forsythe, Paul; Bienenstock, John; Stanisz, Greg J

    2016-01-15

    The gut microbiome has been shown to regulate the development and functions of the enteric and central nervous systems. Its involvement in the regulation of behavior has attracted particular attention because of its potential translational importance in clinical disorders, however little is known about the pathways involved. We previously have demonstrated that administration of Lactobacillus rhamnosus (JB-1) to healthy male BALB/c mice, promotes consistent changes in GABA-A and -B receptor sub-types in specific brain regions, accompanied by reductions in anxiety and depression-related behaviors. In the present study, using magnetic resonance spectroscopy (MRS), we quantitatively assessed two clinically validated biomarkers of brain activity and function, glutamate+glutamine (Glx) and total N-acetyl aspartate+N-acetyl aspartyl glutamic acid (tNAA), as well as GABA, the chief brain inhibitory neurotransmitter. Mice received 1×10(9) cfu of JB-1 per day for 4weeks and were subjected to MRS weekly and again 4weeks after cessation of treatment to ascertain temporal changes in these neurometabolites. Baseline concentrations for Glx, tNAA and GABA were equal to 10.4±0.3mM, 8.7±0.1mM, and 1.2±0.1mM, respectively. Delayed increases were first seen for Glx (~10%) and NAA (~37%) at 2weeks which persisted only to the end of treatment. However, Glx was still elevated 4weeks after treatment had ceased. Significantly elevated GABA (~25%) was only seen at 4weeks. These results suggest specific metabolic pathways in our pursuit of mechanisms of action of psychoactive bacteria. They also offer through application of standard clinical neurodiagnostic techniques, translational opportunities to assess biomarkers accompanying behavioral changes induced by alterations in the gut microbiome. PMID:26577887

  10. The ratio of N-acetyl aspartate to glutamate correlates with disease duration of amyotrophic lateral sclerosis.

    PubMed

    Sako, Wataru; Abe, Takashi; Izumi, Yuishin; Harada, Masafumi; Kaji, Ryuji

    2016-05-01

    Glutamate (Glu)-induced excitotoxicity has been implicated in the neuronal loss of amyotrophic lateral sclerosis. To test the hypothesis that Glu in the primary motor cortex contributes to disease severity and/or duration, the Glu level was investigated using MR spectroscopy. Seventeen patients with amyotrophic lateral sclerosis were diagnosed according to the El Escorial criteria for suspected, possible, probable or definite amyotrophic lateral sclerosis, and enrolled in this cross-sectional study. We measured metabolite concentrations, including N-acetyl aspartate (NAA), creatine, choline, inositol, Glu and glutamine, and performed partial correlation between each metabolite concentration or NAA/Glu ratio and disease severity or duration using age as a covariate. Considering our hypothesis that Glu is associated with neuronal cell death in amyotrophic lateral sclerosis, we investigated the ratio of NAA to Glu, and found a significant correlation between NAA/Glu and disease duration (r=-0.574, p=0.02). The "suspected" amyotrophic lateral sclerosis patients showed the same tendency as possible, probable and definite amyotrophic lateral sclerosis patients in regard to correlation of NAA/Glu ratio with disease duration. The other metabolites showed no significant correlation. Our findings suggested that glutamatergic neurons are less vulnerable compared to other neurons and this may be because inhibitory receptors are mainly located presynaptically, which supports the notion of Glu-induced excitotoxicity. PMID:26765768

  11. Direct determination of the N-acetyl-L-aspartate synthesis rate in the human brain by (13)C MRS and [1-(13)C]glucose infusion.

    PubMed

    Moreno, A; Ross, B D; Blüml, S

    2001-04-01

    A non-invasive (13)C magnetic resonance spectroscopy (MRS) technique is described for the determination of the N-acetyl-L-aspartate (NAA) synthesis rate, V(NAA), in the human brain in vivo. In controls, the mean V(NAA) was 9.2 +/- 3.9 nmol/min/g. In Canavan disease, where [NAA] is increased (p < 0.001) and [aspartate] is deceased (p < 0.001), V(NAA) was significantly reduced to 3.6 +/- 0.1 nmol/min/g (p < 0.001). These rates are in close agreement with the activity of the biosynthetic enzyme measured in vitro in animals, and with the rate of urinary excretion of NAA in human subjects with Canavan disease. The present result is consistent with the regulation of NAA synthesis by the activity of a single enzyme, L-aspartate-N-acetyltransferase, in vivo, and with its control in Canavan disease by limited substrate supply and/or product inhibition. The (13)C MRS technique provides the means for further determination of abnormal rates of neuronal NAA synthesis among neurological disorders in which low cerebral [NAA] has been identified. PMID:11279290

  12. The age dependence of T2 relaxation times of N-acetyl aspartate, creatine and choline in the human brain at 3 and 4T.

    PubMed

    Jiru, F; Skoch, A; Wagnerova, D; Dezortova, M; Viskova, J; Profant, O; Syka, J; Hajek, M

    2016-03-01

    Knowledge of the T2 age dependence is of importance for MRS clinical studies involving subject groups with a wide age range. A number of studies have focused on the age dependence of T2 values in the human brain, with rather conflicting results. The aim of this study was to analyze the age dependence of T2 values of N-acetyl aspartate (NAA), creatine (Cr) and choline (Cho) in the human brain using data acquired at 3T and 4T and to assess the influence of the macromolecule (MM) baseline handling on the obtained results. Two distinct groups of young and elderly controls have been measured at 3T (TE = 30-540 ms, 9 young and 11 elderly subjects) and 4T (TE = 10-180 ms, 18 young and 14 elderly subjects) using single-voxel spectroscopy. In addition, MM spectra were measured from two subjects using the inversion-recovery technique at 4T. All spectra were processed with LCModel using basis sets with different MM signals (measured or simulated) and also with MM signals included for a different TE range. Individual estimated T2 values were statistically analyzed using the R programming language for the age dependence of T2 values as well as the influence of the MM baseline handling. A significant decrease of T2 values of NAA and Cr in elderly subjects compared with young subjects was confirmed. The same trend was observed for Cho. Significantly higher T2 values calculated using the measured MM baseline for all studied metabolites at 4T were observed for both young and elderly subjects. To conclude, while the handling of MM and lipid signals may have a significant effect on estimated T2 values, we confirmed the age dependence of T2 values of NAA and Cr and the same trend for Cho in the human brain. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26752593

  13. Pitfalls and advantages of different strategies for the absolute quantification of N-acetyl aspartate, creatine and choline in white and grey matter by 1H-MRS.

    PubMed

    Malucelli, E; Manners, D N; Testa, C; Tonon, C; Lodi, R; Barbiroli, B; Iotti, S

    2009-12-01

    This study extensively investigates different strategies for the absolute quantitation of N-acetyl aspartate, creatine and choline in white and grey matter by (1)H-MRS at 1.5 T. The main focus of this study was to reliably estimate metabolite concentrations while reducing the scan time, which remains as one of the main problems in clinical MRS. Absolute quantitation was based on the water-unsuppressed concentration as the internal standard. We compared strategies based on various experimental protocols and post-processing strategies. Data were obtained from 30 control subjects using a PRESS sequence at several TE to estimate the transverse relaxation time, T(2), of the metabolites. Quantitation was performed with the algorithm QUEST using two different metabolite signal basis sets: a whole-metabolite basis set (WhoM) and a basis set in which the singlet signals were split from the coupled signals (MSM). The basis sets were simulated in vivo for each TE used. Metabolites' T(2)s were then determined by fitting the estimated signal amplitudes of the metabolites obtained at different TEs. Then the absolute concentrations (mM) of the metabolites were assessed for each subject using the estimated signal amplitudes and either the mean estimated relaxation times of all subjects (mean protocol, MP) or the T(2) estimated from the spectra derived from the same subject (individual protocol, IP). Results showed that MP represents a less time-consuming alternative to IP in the quantitation of brain metabolites by (1)H-MRS in both grey and white matter, with a comparable accuracy when performed by MSM. It was also shown that the acquisition time might be further reduced by using a variant of MP, although with reduced accuracy. In this variant, only one water-suppressed and one water-unsuppressed spectra were acquired, drastically reducing the duration of the entire MRS examination. However, statistical analysis highlights the reduced accuracy of MP when performed using Who

  14. Evaluation of the Lactate-to-N-Acetyl-aspartate Ratio Defined With Magnetic Resonance Spectroscopic Imaging Before Radiation Therapy as a New Predictive Marker of the Site of Relapse in Patients With Glioblastoma Multiforme

    SciTech Connect

    Deviers, Alexandra; Ken, Soléakhéna; Filleron, Thomas; Rowland, Benjamin; Laruelo, Andrea; Catalaa, Isabelle; Lubrano, Vincent; Celsis, Pierre; and others

    2014-10-01

    Purpose: Because lactate accumulation is considered a surrogate for hypoxia and tumor radiation resistance, we studied the spatial distribution of the lactate-to-N-acetyl-aspartate ratio (LNR) before radiation therapy (RT) with 3D proton magnetic resonance spectroscopic imaging (3D-{sup 1}H-MRSI) and assessed its impact on local tumor control in glioblastoma (GBM). Methods and Materials: Fourteen patients with newly diagnosed GBM included in a phase 2 chemoradiation therapy trial constituted our database. Magnetic resonance imaging (MRI) and MRSI data before RT were evaluated and correlated to MRI data at relapse. The optimal threshold for tumor-associated LNR was determined with receiver-operating-characteristic (ROC) curve analysis of the pre-RT LNR values and MRI characteristics of the tumor. This threshold was used to segment pre-RT normalized LNR maps. Two spatial analyses were performed: (1) a pre-RT volumetric comparison of abnormal LNR areas with regions of MRI-defined lesions and a choline (Cho)-to- N-acetyl-aspartate (NAA) ratio ≥2 (CNR2); and (2) a voxel-by-voxel spatial analysis of 4,186,185 voxels with the intention of evaluating whether pre-RT abnormal LNR areas were predictive of the site of local recurrence. Results: A LNR of ≥0.4 (LNR-0.4) discriminated between tumor-associated and normal LNR values with 88.8% sensitivity and 97.6% specificity. LNR-0.4 voxels were spatially different from those of MRI-defined lesions, representing 44% of contrast enhancement, 64% of central necrosis, and 26% of fluid-attenuated inversion recovery (FLAIR) abnormality volumes before RT. They extended beyond the overlap with CNR2 for most patients (median: 20 cm{sup 3}; range: 6-49 cm{sup 3}). LNR-0.4 voxels were significantly predictive of local recurrence, regarded as contrast enhancement at relapse: 71% of voxels with a LNR-0.4 before RT were contrast enhanced at relapse versus 10% of voxels with a normal LNR (P<.01). Conclusions: Pre-RT LNR-0.4 in GBM

  15. Brain lithium, N-acetyl aspartate and myo-inositol levels in older adults with bipolar disorder treated with lithium: a lithium-7 and proton magnetic resonance spectroscopy study

    PubMed Central

    Forester, Brent P; Finn, Chelsea T; Berlow, Yosef A; Wardrop, Megan; Renshaw, Perry F; Moore, Constance M

    2014-01-01

    Objectives We investigated the relationship between brain lithium levels and the metabolites N-acetyl aspartate (NAA) and myo-inositol (myo-Ino) in the anterior cingulate cortex of a group of older adults with bipolar disorder (BD). Methods This cross-sectional assessment included nine subjects (six males and three females) with bipolar I disorder and currently treated with lithium, who were examined at McLean Hospital’s Geriatric Psychiatry Research Program and Brain Imaging Center. The subjects’ ages ranged from 56 to 85 years (66.0 ± 9.7 years) and all subjects had measurements of serum and brain lithium levels. Brain lithium levels were assessed using lithium magnetic resonance spectroscopy. All subjects also had proton magnetic resonance spectroscopy to obtain measurements of NAA and myo-Ino. Results Brain lithium levels were associated with higher NAA levels [df = (1, 8), B = 12.53, t = 4.09, p < 0.005] and higher myo-Ino levels [df = (1, 7), F = 16.81, p < 0.006]. There were no significant effects of serum lithium levels on any of the metabolites. Conclusion Our findings of a relationship between higher brain lithium levels and elevated NAA levels in older adult subjects with BD may support previous evidence of lithium’s neuroprotective, neurotrophic, and mitochondrial function-enhancing effects. Elevated myo-Ino related to elevated brain lithium levels may reflect increased inositol monophosphatase (IMPase) activity, which would lead to an increase in myo-Ino levels. This is the first study to demonstrate alterations in NAA and myo-Ino in a sample of older adults with BD treated with lithium. PMID:18837863

  16. No change in N-acetyl aspartate in first episode of moderate depression after antidepressant treatment: 1H magnetic spectroscopy study of left amygdala and left dorsolateral prefrontal cortex

    PubMed Central

    Bajs Janović, Maja; Kalember, Petra; Janović, Špiro; Hrabač, Pero; Folnegović Grošić, Petra; Grošić, Vladimir; Radoš, Marko; Henigsberg, Neven

    2014-01-01

    Background The role of brain metabolites as biological correlates of the intensity, symptoms, and course of major depression has not been determined. It has also been inconclusive whether the change in brain metabolites, measured with proton magnetic spectroscopy, could be correlated with the treatment outcome. Methods Proton magnetic spectroscopy was performed in 29 participants with a first episode of moderate depression occurring in the left dorsolateral prefrontal cortex and left amygdala at baseline and after 8 weeks of antidepressant treatment with escitalopram. The Montgomery-Asberg Depression Rating Scale, the Hamilton Rating Scale for Depression, and the Beck Depression Inventory were used to assess the intensity of depression at baseline and at the endpoint of the study. At endpoint, the participants were identified as responders (n=17) or nonresponders (n=12) to the antidepressant therapy. Results There was no significant change in the N-acetyl aspartate/creatine ratio (NAA/Cr) after treatment with antidepressant medication. The baseline and endpoint NAA/Cr ratios were not significantly different between the responder and nonresponder groups. The correlation between NAA/Cr and changes in the scores of clinical scales were not significant in either group. Conclusion This study could not confirm any significant changes in NAA after antidepressant treatment in the first episode of moderate depression, or in regard to therapy response in the left dorsolateral prefrontal cortex or left amygdala. Further research is necessary to conclude whether NAA alterations in the first episode of depression could possibly be different from chronic or late-onset depression, and whether NAA alterations in stress-induced (reactive) depression are different from endogenous depression. The potential role of NAA as a biomarker of a treatment effect has yet to be established. PMID:25278754

  17. Comparative analysis of pharmacological treatments with N-acetyl-dl-leucine (Tanganil) and its two isomers (N-acetyl-L-leucine and N-acetyl-D-leucine) on vestibular compensation: Behavioral investigation in the cat.

    PubMed

    Tighilet, Brahim; Leonard, Jacques; Bernard-Demanze, Laurence; Lacour, Michel

    2015-12-15

    Head roll tilt, postural imbalance and spontaneous nystagmus are the main static vestibular deficits observed after an acute unilateral vestibular loss (UVL). In the UVL cat model, these deficits are fully compensated over 6 weeks as the result of central vestibular compensation. N-Acetyl-dl-leucine is a drug prescribed in clinical practice for the symptomatic treatment of acute UVL patients. The present study investigated the effects of N-acetyl-dl-leucine on the behavioral recovery after unilateral vestibular neurectomy (UVN) in the cat, and compared the effects of each of its two isomers N-acetyl-L-leucine and N-acetyl-D-leucine. Efficacy of these three drug treatments has been evaluated with respect to a placebo group (UVN+saline water) on the global sensorimotor activity (observation grids), the posture control (support surface measurement), the locomotor balance (maximum performance at the rotating beam test), and the spontaneous vestibular nystagmus (recorded in the light). Whatever the parameters tested, the behavioral recovery was strongly and significantly accelerated under pharmacological treatments with N-acetyl-dl-leucine and N-acetyl-L-leucine. In contrast, the N-acetyl-D-leucine isomer had no effect at all on the behavioral recovery, and animals of this group showed the same recovery profile as those receiving a placebo. It is concluded that the N-acetyl-L-leucine isomer is the active part of the racemate component since it induces a significant acceleration of the vestibular compensation process similar (and even better) to that observed under treatment with the racemate component only. PMID:26607469

  18. The Structure- and Metal-dependent Activity of Escherichia coli PgaB Provides Insight into the Partial De-N-acetylation of Poly-β-1,6-N-acetyl-d-glucosamine*

    PubMed Central

    Little, Dustin J.; Poloczek, Joanna; Whitney, John C.; Robinson, Howard; Nitz, Mark; Howell, P. Lynne

    2012-01-01

    Exopolysaccharides are required for the development and integrity of biofilms produced by a wide variety of bacteria. In Escherichia coli, partial de-N-acetylation of the exopolysaccharide poly-β-1,6-N-acetyl-d-glucosamine (PNAG) by the periplasmic protein PgaB is required for polysaccharide intercellular adhesin-dependent biofilm formation. To understand the molecular basis for PNAG de-N-acetylation, the structure of PgaB in complex with Ni2+ and Fe3+ have been determined to 1.9 and 2.1 Å resolution, respectively, and its activity on β-1,6-GlcNAc oligomers has been characterized. The structure of PgaB reveals two (β/α)x barrel domains: a metal-binding de-N-acetylase that is a member of the family 4 carbohydrate esterases (CE4s) and a domain structurally similar to glycoside hydrolases. PgaB displays de-N-acetylase activity on β-1,6-GlcNAc oligomers but not on the β-1,4-(GlcNAc)4 oligomer chitotetraose and is the first CE4 member to exhibit this substrate specificity. De-N-acetylation occurs in a length-dependent manor, and specificity is observed for the position of de-N-acetylation. A key aspartic acid involved in de-N-acetylation, normally seen in other CE4s, is missing in PgaB, suggesting that the activity of PgaB is attenuated to maintain the low levels of de-N-acetylation of PNAG observed in vivo. The metal dependence of PgaB is different from most CE4s, because PgaB shows increased rates of de-N-acetylation with Co2+ and Ni2+ under aerobic conditions, and Co2+, Ni2+ and Fe2+ under anaerobic conditions, but decreased activity with Zn2+. The work presented herein will guide inhibitor design to combat biofilm formation by E. coli and potentially a wide range of medically relevant bacteria producing polysaccharide intercellular adhesin-dependent biofilms. PMID:22810235

  19. 21 CFR 172.372 - N-Acetyl-L-methionine.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false N-Acetyl-L-methionine. 172.372 Section 172.372 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.372 N-Acetyl-L-methionine....

  20. In vivo N-acetyl cysteine reduce hepatocyte death by induced acetaminophen

    NASA Astrophysics Data System (ADS)

    Lin, Chih-Ju; Li, Feng-Chieh; Wang, Sheng-Shun; Lee, Hsuan-Shu; Dong, Chen-Yuan

    2011-07-01

    Acetaminophen (APAP) is the famous drug in global, and taking overdose Acetaminophen will intake hepatic cell injure. Desptie substantial progress in our understanding of the mechanism of hepatocellular injury during the last 40 years, many aspects of the pathophysiology are still unknown or controversial.1 In this study, mice are injected APAP overdose to damage hepatocyte. APAP deplete glutathione and ATP of cell, N-Acetyl Cysteine (NAC) plays an important role to protect hepatocytes be injury. N-Acetyl Cysteine provides mitochondrial to produce glutathione to release drug effect hepatocyte. By 6-carboxyfluorescein diacetate (6-CFDA) metabolism in vivo, glutathione keep depleting to observe the hepatocyte morphology in time. Without NAC, cell necrosis increase to plasma membrane damage to release 6-CFDA, that's rupture. After 6-CFDA injection, fluorescence will be retained in hepatocyte. For cell retain with NAC and without NAC are almost the same. With NAC, the number of cell rupture decreases about 75%.

  1. Quantification of N-Acetyl Aspartyl Glutamate in Human Brain using Proton Magnetic Resonance Spectroscopy at 7 T

    NASA Astrophysics Data System (ADS)

    Elywa, M.

    2015-07-01

    The separation of N-acetyl aspartyl glutamate (NAAG) from N-acetyl aspartate (NAA) and other metabolites, such as glutamate, by in vivo proton magnetic resonance spectroscopy at 7 T is described. This method is based on the stimulated echo acquisition mode (STEAM), with short and long echo time (TE) and allows quantitative measurements of NAAG in the parietal and pregenual anterior cingulate cortex (pgACC) of human brain. Two basesets for the LCModel have been established using nuclear magnetic resonance simulator software (NMR-SIM). Six healthy volunteers (age 25-35 years) have been examined at 7 T. It has been established that NAAG can be separated and quantified in the parietal location and does not get quantified in the pgACC location when using a short echo time, TE = 20 ms. On the other hand, by using a long echo time, TE = 74 ms, NAAG can be quantified in pgACC structures.

  2. Chitosan Molecular Structure as a Function of N-Acetylation

    SciTech Connect

    Franca, Eduardo F.; Freitas, Luiz C.; Lins, Roberto D.

    2011-07-01

    Molecular dynamics simulations have been carried out to characterize the structure and solubility of chitosan nanoparticle-like structures as a function of the deacetylation level (0, 40, 60, and 100%) and the spatial distribution of the N-acetyl groups in the particles. The polysaccharide chains of highly N-deacetylated particles where the N-acetyl groups are uniformly distributed present a high flexibility and preference for the relaxed two-fold helix and five-fold helix motifs. When these groups are confined to a given region of the particle, the chains adopt preferentially a two-fold helix with f and w values close to crystalline chitin. Nanoparticles with up to 40% acetylation are moderately soluble, forming stable aggregates when the N-acetyl groups are unevenly distributed. Systems with 60% or higher N-acetylation levels are insoluble and present similar degrees of swelling regardless the distribution of their N-acetyl groups. Overall particle solvation is highly affected by electrostatic forces resulting from the degree of acetylation. The water mobility and orientation around the polysaccharide chains affects the stability of the intramolecular O3- HO3(n) ... O5(n+ 1) hydrogen bond, which in turn controls particle aggregation.

  3. [Spectrophotometric evaluation of N-acetyl-beta-glucosaminidase in urine].

    PubMed

    Potere, C; Di Cosmo, C; Riario-Sforza, G; Di Silverio, F; Albertazzi, A; Cappelli, P

    1982-01-01

    A spectrophotometric method for the assay of N-Acetyl-beta-Glucosaminidase activity in human undiluted urines is described. The application of this method is recommended for its sensitivity (2,6 X 10(-4)M) and its rapid performance, because it represents a good alternative to current methods and essentially to the fluorimetric technique with which it has a significant statistical correlation. Estimates of normal individuals aged between 1-70 years are reported. PMID:7168631

  4. Aspartic acid

    MedlinePlus

    ... also called asparaginic acid. Aspartic acid helps every cell in the body work. It plays a role in: Hormone production and release Normal nervous system function Plant sources of aspartic acid include: Legumes such as ...

  5. N-acetyl-aspartyl-glutamate and inhibition of glutamate carboxypeptidases protects against soman-induced neuropathology.

    PubMed

    Guo, Huifu; Liu, Jiong; Van Shura, Kerry; Chen, HuaZhen; Flora, Michael N; Myers, Todd M; McDonough, John H; McCabe, Joseph T

    2015-05-01

    N-acetyl-aspartyl-glutamate (NAAG) is the most abundant neuropeptide in the mammalian brain. In a variety of animal models of brain injury, the administration of NAAG-related compounds, or inhibitors of glutamate carboxypeptidases (GCPs; the enzymes that hydrolyze NAAG), were shown to be neuroprotective. This study determined the impact of the administration of three NAAG-related compounds, NAAG, β-NAAG (a NAAG homologue resistant to degradation), and 2-phosphonomethyl pentanedioic acid (2-PMPA; an inhibitor of GCP enzymes), on the neuropathology that develops following exposure to the nerve agent, soman. When given 1 min after soman exposure, NAAG-related drug treatments did not alter the survival rate or body weight loss seen 24 h after rats were exposed to soman. Likewise, brain levels of both NAAG and its metabolite, N-acetyl-aspartate (NAA), were substantially decreased 24 h after soman, and in particularly vulnerable brain regions the drug treatments were unable to attenuate the reduction in NAA and NAAG levels. Histochemical study indicated there was a dramatic increase in Fluoro-Jade C (FJC) staining, indicative of neuron cell death, 24 h after soman exposure. However, in the amygdala and in the entorhinal and piriform limbic cortex, which sustained severe neuropathology following soman intoxication, single or combined injections of NAAG compounds and 2-PMPA significantly reduced the number of FJC-positive cells, and effect size estimates suggest that in some brain regions the treatments were effective. The findings suggest that NAAG neurotransmission in the central nervous system is significantly altered by soman exposure, and that the administration of NAAG-related compounds and 2-PMPA reduces neuron cell death in brain regions that sustain severe damage. PMID:25825357

  6. Decoupling of N-acetyl-aspartate and Glutamate Within the Dorsolateral Prefrontal Cortex in Schizophrenia

    PubMed Central

    Coughlin, Jennifer M.; Tanaka, Teppei; Marsman, Anouk; Wang, Hongxing; Bonekamp, Susanne; Kim, Pearl K.; Higgs, Cecilia; Varvaris, Mark; Edden, Richard A.E.; Pomper, Martin; Schretlen, David; Barker, Peter B.; Sawa, Akira

    2015-01-01

    Aberrant function of glutamatergic pathways is likely to underlie the pathology of schizophrenia. Evidence of oxidative stress in the disease pathology has also been reported. N-Acetylaspartate (NAA) is metabolically linked to both cascades and may be a key marker in exploring the interconnection of glutamatergic pathways and oxidative stress. Several studies have reported positive correlation between the levels of NAA and Glx (the sum of glutamate and glutamine) in several brain regions in healthy subjects, by using proton magnetic resonance spectroscopy ([1H]MRS). Interestingly, one research group recently reported decoupling of the relationship between NAA and Glx in the hippocampus of patients with schizophrenia. Here we report levels of NAA and Glx measured using [1H]MRS, relative to the level of creatine (Cr) as an internal control. The dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC) in 25 patients with schizophrenia and 17 matched healthy controls were studied. In DLPFC, NAA/Cr and Glx/Cr were significantly positively correlated in healthy controls after correction for the effect of age and smoking status and after correction for multiple comparisons (r= 0.63, P= 0.017). However, in patients with schizophrenia, the positive correlation between NAA/Cr and Glx/Cr was not observed even after correcting for these two variables (r= −0.33, P= 0.124). Positive correlation between NAA/Cr and Glx/Cr was not observed in the ACC in both groups. Decoupling of NAA and Glx in the DLPFC may reflect the interconnection of glutamatergic pathways and oxidative stress in the pathology of schizophrenia, and may possibly be a biomarker of the disease. PMID:25732147

  7. N-Acetyl-4-aminophenol (paracetamol), N-acetyl-2-aminophenol and acetanilide in urine samples from the general population, individuals exposed to aniline and paracetamol users.

    PubMed

    Dierkes, Georg; Weiss, Tobias; Modick, Hendrik; Käfferlein, Heiko Udo; Brüning, Thomas; Koch, Holger M

    2014-01-01

    Epidemiological studies suggest associations between the use of N-acetyl-4-aminophenol (paracetamol) during pregnancy and increased risks of reproductive disorders in the male offspring. Previously we have reported a ubiquitous urinary excretion of N-acetyl-4-aminophenol in the general population. Possible sources are (1) direct intake of paracetamol through medication, (2) paracetamol residues in the food chain and (3) environmental exposure to aniline or related substances that are metabolized into N-acetyl-4-aminophenol. In order to elucidate the origins of the excretion of N-acetyl-4-aminophenol in urine and to contribute to the understanding of paracetamol and aniline metabolism in humans we developed a rapid, turbulent-flow HPLC-MS/MS method with isotope dilution for the simultaneous quantification of N-acetyl-4-aminophenol and two other aniline related metabolites, N-acetyl-2-aminophenol and acetanilide. We applied this method to three sets of urine samples: (1) individuals with no known exposure to aniline and also no recent paracetamol medication; (2) individuals after occupational exposure to aniline but no paracetamol medication and (3) paracetamol users. We confirmed the omnipresent excretion of N-acetyl-4-aminophenol. Additionally we revealed an omnipresent excretion of N-acetyl-2-aminophenol. In contrast, acetanilide was only found after occupational exposure to aniline, not in the general population or after paracetamol use. The results lead to four preliminary conclusions: (1) other sources than aniline seem to be responsible for the major part of urinary N-acetyl-4-aminophenol in the general population; (2) acetanilide is a metabolite of aniline in man and a valuable biomarker for aniline in occupational settings; (3) aniline baseline levels in the general population measured after chemical hydrolysis do not seem to originate from acetanilide and hence not from a direct exposure to aniline itself and (4) N-acetyl-2-aminophenol does not seem to be

  8. Efficacy of N-Acetyl Cysteine in Traumatic Brain Injury

    PubMed Central

    Eakin, Katharine; Baratz-Goldstein, Renana; Pick, Chiam G.; Zindel, Ofra; Balaban, Carey D.; Hoffer, Michael E.; Lockwood, Megan; Miller, Jonathan; Hoffer, Barry J.

    2014-01-01

    In this study, using two different injury models in two different species, we found that early post-injury treatment with N-Acetyl Cysteine (NAC) reversed the behavioral deficits associated with the TBI. These data suggest generalization of a protocol similar to our recent clinical trial with NAC in blast-induced mTBI in a battlefield setting [1], to mild concussion from blunt trauma. This study used both weight drop in mice and fluid percussion injury in rats. These were chosen to simulate either mild or moderate traumatic brain injury (TBI). For mice, we used novel object recognition and the Y maze. For rats, we used the Morris water maze. NAC was administered beginning 30–60 minutes after injury. Behavioral deficits due to injury in both species were significantly reversed by NAC treatment. We thus conclude NAC produces significant behavioral recovery after injury. Future preclinical studies are needed to define the mechanism of action, perhaps leading to more effective therapies in man. PMID:24740427

  9. Central N-acetyl aspartylglutamate deficit: a possible pathogenesis of schizophrenia.

    PubMed

    Tsai, Shih-Jen

    2005-09-01

    The "glutamate hypothesis" of schizophrenia has emerged from the finding that phencyclidine (PCP) induces psychotic-like behaviors in rodents, possibly by blocking the N-methyl-D-aspartate (NMDA) subtype of glutamate receptor, thereby causing increased glutamate release. N-acetyl aspartylglutamate (NAAG), an endogenous peptide abundant in mammalian nervous systems, is localized in certain brain cells, including cortical and hippocampal pyramidal neurons. NAAG is synthesized from N-acetylaspartate (NAA) and glutamate, and NAA availability may limit the rate of NAAG synthesis. Although NAAG is known to have some neurotransmitter-like functions, NAA does not. NAAG is a highly selective agonist of the type 3 metabotropic glutamate receptor (mGluR3, a presynaptic autoreceptor) and can inhibit glutamate release. In addition, at low levels, NAAG is an NMDA receptor antagonist, and blocking of NMDA receptors may increase glutamate release. Taken together, low central NAAG levels may antagonize the effect of glutamate at NMDA receptors and decrease its agonistic effect on presynaptic mGluR3; both activities could increase glutamate release, similar to the increase demonstrated in the PCP model of schizophrenia. In this report, it is suggested that the central NAAG deficit, possibly through decreased synthesis or increased degradation of NAAG, may play a role in the pathogenesis of schizophrenia. Evidence is presented and discussed from magnetic resonance, postmortem, animal model, schizophrenia treatment, and genetic studies. The central NAAG deficit model of schizophrenia could explain the disease process, from the perspectives of both neurodevelopment and neurodegeneration, and may point to potential treatments for schizophrenia. PMID:16127367

  10. Glutathione precursor, N-acetyl-cysteine, improves mismatch negativity in schizophrenia patients.

    PubMed

    Lavoie, Suzie; Murray, Micah M; Deppen, Patricia; Knyazeva, Maria G; Berk, Michael; Boulat, Olivier; Bovet, Pierre; Bush, Ashley I; Conus, Philippe; Copolov, David; Fornari, Eleonora; Meuli, Reto; Solida, Alessandra; Vianin, Pascal; Cuénod, Michel; Buclin, Thierry; Do, Kim Q

    2008-08-01

    In schizophrenia patients, glutathione dysregulation at the gene, protein and functional levels, leads to N-methyl-D-aspartate (NMDA) receptor hypofunction. These patients also exhibit deficits in auditory sensory processing that manifests as impaired mismatch negativity (MMN), which is an auditory evoked potential (AEP) component related to NMDA receptor function. N-acetyl-cysteine (NAC), a glutathione precursor, was administered to patients to determine whether increased levels of brain glutathione would improve MMN and by extension NMDA function. A randomized, double-blind, cross-over protocol was conducted, entailing the administration of NAC (2 g/day) for 60 days and then placebo for another 60 days (or vice versa). 128-channel AEPs were recorded during a frequency oddball discrimination task at protocol onset, at the point of cross-over, and at the end of the study. At the onset of the protocol, the MMN of patients was significantly impaired compared to sex- and age- matched healthy controls (p=0.003), without any evidence of concomitant P300 component deficits. Treatment with NAC significantly improved MMN generation compared with placebo (p=0.025) without any measurable effects on the P300 component. MMN improvement was observed in the absence of robust changes in assessments of clinical severity, though the latter was observed in a larger and more prolonged clinical study. This pattern suggests that MMN enhancement may precede changes to indices of clinical severity, highlighting the possible utility AEPs as a biomarker of treatment efficacy. The improvement of this functional marker may indicate an important pathway towards new therapeutic strategies that target glutathione dysregulation in schizophrenia. PMID:18004285

  11. 40 CFR 180.1089 - Poly-N-acetyl-D-glucosamine; exemption from the requirement of tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Poly-N-acetyl-D-glucosamine; exemption... FOOD Exemptions From Tolerances § 180.1089 Poly-N-acetyl-D-glucosamine; exemption from the requirement... biochemical nematicide poly-N-acetyl-D-glucosamine on a variety of agricultural crops....

  12. Adjunctive N-acetyl-L-cysteine in treatment of murine pneumococcal meningitis.

    PubMed

    Högen, Tobias; Demel, Cornelia; Giese, Armin; Angele, Barbara; Pfister, Hans-Walter; Koedel, Uwe; Klein, Matthias

    2013-10-01

    Despite antibiotic therapy, acute and long-term complications are still frequent in pneumococcal meningitis. One important trigger of these complications is oxidative stress, and adjunctive antioxidant treatment with N-acetyl-l-cysteine was suggested to be protective in experimental pneumococcal meningitis. However, studies of effects on neurological long-term sequelae are limited. Here, we investigated the impact of adjunctive N-acetyl-l-cysteine on long-term neurological deficits in a mouse model of meningitis. C57BL/6 mice were intracisternally infected with Streptococcus pneumoniae. Eighteen hours after infection, mice were treated with a combination of ceftriaxone and placebo or ceftriaxone and N-acetyl-l-cysteine, respectively. Two weeks after infection, neurologic deficits were assessed using a clinical score, an open field test (explorative activity), a t-maze test (memory function), and auditory brain stem responses (hearing loss). Furthermore, cochlear histomorphological correlates of hearing loss were assessed. Adjunctive N-acetyl-l-cysteine reduced hearing loss after pneumococcal meningitis, but the effect was minor. There was no significant benefit of adjunctive N-acetyl-l-cysteine treatment in regard to other long-term complications of pneumococcal meningitis. Cochlear morphological correlates of meningitis-associated hearing loss were not reduced by adjunctive N-acetyl-l-cysteine. In conclusion, adjunctive therapy with N-acetyl-l-cysteine at a dosage of 300 mg/kg of body weight intraperitoneally for 4 days reduced hearing loss but not other neurologic deficits after pneumococcal meningitis in mice. These results make a clinical therapeutic benefit of N-acetyl-l-cysteine in the treatment of patients with pneumococcal meningitis questionable. PMID:23877681

  13. N-acetyl-l-tryptophan, but not N-acetyl-d-tryptophan, rescues neuronal cell death in models of amyotrophic lateral sclerosis.

    PubMed

    Sirianni, Ana C; Jiang, Jiying; Zeng, Jiang; Mao, Lilly L; Zhou, Shuanhu; Sugarbaker, Peter; Zhang, Xinmu; Li, Wei; Friedlander, Robert M; Wang, Xin

    2015-09-01

    Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive motor neuron loss. Evidence suggests that mitochondrial dysfunction, apoptosis, oxidative stress, inflammation, glutamate excitotoxicity, and proteasomal dysfunction are all responsible for ALS pathogenesis. N-acetyl-tryptophan has been identified as an inhibitor of mitochondrial cytochrome c release and therefore is a potential neuroprotective agent. By quantifying cell death, we demonstrate that N-acetyl-l-tryptophan (L-NAT) and N-acetyl-DL-tryptophan are neuroprotective in NSC-34 motor neuron-like cells and/or primary motor neurons, while their isomer N-acetyl-d-tryptophan has no protective effect. These findings are consistent with energy minimization and molecular modeling analysis, confirming that L-NAT generates the most stable complex with the neurokinin-1 receptor (NK-1R). L-NAT inhibits the secretion of Substance P and IL-1β (Enzyme-Linked Immunosorbent Assay and/or dot blots) and mitochondrial dysfunction by effectively inhibiting the release of cytochrome c/Smac/AIF from mitochondria into the cytoplasm and activation of apoptotic pathways, including the activation of caspase-1, -9, and -3, as well as proteasomal dysfunction through restoring chymotrypsin-like, trypsin-like, and caspase-like proteasome activity. These data provide insight into the molecular mechanisms by which L-NAT offers neuroprotection in models of ALS and suggest its potential as a novel therapeutic strategy for ALS. We demonstrate that L-NAT (N-acetyl-l-tryptophan), but not D-NAT, rescues NSC-34 cells and primary motor neurons from cell death. L-NAT inhibits the secretion of Substance P and IL-1β, and caspase-1 activation, the release of cytochrome c/Smac/AIF, and the activation of caspase -9, and -3, as well as proteasomal dysfunction. The data suggest the potential of L-NAT as a novel therapeutic strategy for amyotrophic lateral sclerosis (ALS). AIF, apoptosis-inducing factor. PMID

  14. Radiolysis of N-acetyl amino acids as model compounds for radiation degradation of polypeptides

    NASA Astrophysics Data System (ADS)

    Wayne Garrett, R.; Hill, David J. T.; Ho, Sook-Ying; O'Donnell, James H.; O'Sullivan, Paul W.; Pomery, Peter J.

    Radiation chemical yields of (i) the volatile radiolysis products and (ii) the trapped free radicals from the y-radiolysis of the N-acetyl derivatives of glycine, L-valine, L-phenylalanine and L-tyrosine in the polycrystalline state have been determined at room temperature (303 K). Carbon dioxide was found to be the major molecular product for all these compounds with G(CO 2) varying from 0.36 for N-acetyl-L-tyrosine to 8 for N-acetyl-L-valine. There was evidence for some scission of the N-C α bond, indicated by the production of acetamide and the corresponding aliphatic acid, but the determination reaction was found to be of much lesser importance than the decarboxylation reaction. A protective effect of the aromatic ring in N-acetyl-L-phenylalanine and in N-acetyl-L-tyrosine was indicated by the lower yields of volatile products for these compounds. The yields of trapped free radicals were found to vary with the nature of the amino acid side chain, increasing with chain length and chain branching. The radical yields were decreased by incorporation of an aromatic moiety in the side chain, this effect being greater for the tyrosyl side chain than for the phenyl side chain. The G(R·) values showed a good correlation with G(CO 2) indicating that a common reaction may be involved in radical production and carbon dioxide formation.

  15. Determination of DNA damage in experimental liver intoxication and role of N-acetyl cysteine.

    PubMed

    Aksit, Hasan; Bildik, Aysegül

    2014-11-01

    The present study aimed at detecting DNA damage and fragmentation as well as histone acetylation depending on oxidative stress caused by CCl4 intoxication. Also, the protective role of N-acetyl cysteine, a precursor for GSH, in DNA damage is investigated. Sixty rats were used in this study. In order to induce liver toxicity, CCl4 in was dissolved in olive oil (1/1) and injected intraperitoneally as a single dose (2 ml/kg). N-acetyl cysteine application (intraperitoneal, 50 mg/kg/day) was started 3 days prior to CCl4 injection and continued during the experimental period. Control groups were given olive oil and N-acetyl cysteine. After 6 and 72 h of CCl4 injection, blood and liver tissue were taken under ether anesthesia. Nuclear extracts were prepared from liver. Changes in serum AST and ALT activities as well as MDA, TAS, and TOS levels showed that CCl4 caused lipid peroxidation and liver damage. However, lipid peroxidation and liver damage were reduced in the N-acetyl cysteine group. Increased levels in 8-hydroxy-2-deoxy guanosine and histone acetyltransferase activities, decreased histone deacetylase activities, and DNA breakage detected in nuclear extracts showed that CCl4 intoxication induces oxidative stress and apoptosis in rat liver. The results of the present study indicate that N-acetyl cysteine has a protective effect on CCl4-induced DNA damage. PMID:24819310

  16. Conformational studies of bacterial peptidoglycan: structure and stereochemistry of N-acetyl-β- D-glucosamine and N-acetyl-β- D-muramic acid

    NASA Astrophysics Data System (ADS)

    Yadav, P. N. S.; Rai, D. K.; Yadav, J. S.

    1989-03-01

    The energies of various conformations of N-acetyl-β- D-glucosamine (NAG) and its 3-O- D-lactic acid derivative N-acetyl-β- D-muramic acid (NAM) have been calculated by geometry optimization using the molecular mechanics program MM2. The geometries of these systems have been analyzed in the light of ring torsion, bond lengths, bond angles and conformational states of side groups of the pyranosyl ring and compared with available experimental data of similar pyranose derivatives. The present study indicates the presence of hydrogen bonds to stabilize the side group conformations. Discrepancies with experimental data that are seen in a few cases are ascribed to the nature of the side groups and their geometry.

  17. Catalytic Depolymerization of Chitin with Retention of N-Acetyl Group.

    PubMed

    Yabushita, Mizuho; Kobayashi, Hirokazu; Kuroki, Kyoichi; Ito, Shogo; Fukuoka, Atsushi

    2015-11-01

    Chitin, a polymer of N-acetylglucosamine units with β-1,4-glycosidic linkages, is the most abundant marine biomass. Chitin monomers containing N-acetyl groups are useful precursors to various fine chemicals and medicines. However, the selective conversion of robust chitin to N-acetylated monomers currently requires a large excess of acid or a long reaction time, which limits its application. We demonstrate a fast catalytic transformation of chitin to monomers with retention of N-acetyl groups by combining mechanochemistry and homogeneous catalysis. Mechanical-force-assisted depolymerization of chitin with a catalytic amount of H2SO4 gave soluble short-chain oligomers. Subsequent hydrolysis of the ball-milled sample provided N-acetylglucosamine in 53% yield, and methanolysis afforded 1-O-methyl-N-acetylglucosamine in yields of up to 70%. Our process can greatly reduce the use of acid compared to the conventional process. PMID:26538108

  18. Structural Basis for the De-N-acetylation of Poly-β-1,6-N-acetyl-d-glucosamine in Gram-positive Bacteria*

    PubMed Central

    Little, Dustin J.; Bamford, Natalie C.; Pokrovskaya, Varvara; Robinson, Howard; Nitz, Mark; Howell, P. Lynne

    2014-01-01

    Exopolysaccharides are required for the development and integrity of biofilms produced by a wide variety of bacteria. In staphylococci, partial de-N-acetylation of the exopolysaccharide poly-β-1,6-N-acetyl-d-glucosamine (PNAG) by the extracellular protein IcaB is required for biofilm formation. To understand the molecular basis for PNAG de-N-acetylation, the structure of IcaB from Ammonifex degensii (IcaBAd) has been determined to 1.7 Å resolution. The structure of IcaBAd reveals a (β/α)7 barrel common to the family four carbohydrate esterases (CE4s) with the canonical motifs circularly permuted. The metal dependence of IcaBAd is similar to most CE4s showing the maximum rates of de-N-acetylation with Ni2+, Co2+, and Zn2+. From docking studies with β-1,6-GlcNAc oligomers and structural comparison to PgaB from Escherichia coli, the Gram-negative homologue of IcaB, we identify Arg-45, Tyr-67, and Trp-180 as key residues for PNAG binding during catalysis. The absence of these residues in PgaB provides a rationale for the requirement of a C-terminal domain for efficient deacetylation of PNAG in Gram-negative species. Mutational analysis of conserved active site residues suggests that IcaB uses an altered catalytic mechanism in comparison to other characterized CE4 members. Furthermore, we identified a conserved surface-exposed hydrophobic loop found only in Gram-positive homologues of IcaB. Our data suggest that this loop is required for membrane association and likely anchors IcaB to the membrane during polysaccharide biosynthesis. The work presented herein will help guide the design of IcaB inhibitors to combat biofilm formation by staphylococci. PMID:25359777

  19. Quantitative measurement of N-acetyl-aspartyl-glutamate at 3 T using TE-averaged PRESS spectroscopy and regularized lineshape deconvolution.

    PubMed

    Zhang, Yan; Li, Shizhe; Marenco, Stefano; Shen, Jun

    2011-08-01

    This article introduces regularized lineshape deconvolution in conjunction with TE-averaged PRESS spectroscopy to measure N-acetyl-aspartyl-glutamate (NAAG). Averaging different echo times suppressed the signals of multiplets from strongly coupled spin systems near 2 ppm; thus, minimizing the interfering signals to detect the acetyl proton signal of NAAG. Signal distortion was corrected by lineshape deconvolution, and Tikhonov regularization was introduced to reduce noise amplification arising from deconvolution; as a result, spectral resolution was enhanced without significantly sacrificing signal-to-noise ratio (SNR). This new approach was used to measure NAAG in the two regions of interest of healthy volunteers, dominated by gray matter and white matter, respectively. The acetyl proton signal of NAAG was directly quantified by fitting the deconvoluted spectra to a Voigt-lineshape spectral model function, yielding the NAAG-N-acetyl-aspartate (NAA) ratios of 0.11±0.02 for the gray matter voxels (n=8) and 0.18±0.02 for the white matter voxels (n=12). PMID:21656565

  20. Mucolipidosis III β-N-acetyl-d-hexosaminidase A. Purification and properties

    PubMed Central

    Kress, Barry C.; Hirani, Shirish; Freeze, Hudson H.; Little, Laureen; Miller, Arnold L.

    1982-01-01

    Mucolipidosis III acid hydrolases possess an altered carbohydrate recognition marker needed for their lysosomal localization. As a result of this alteration, a portion of these enzymes is secreted from the cell to the extracellular spaces. The structural changes that may have occurred to one of these secreted enzymes, β-N-acetyl-d-hexosaminidase A (EC 3.2.1.52) were investigated. Normal and mucolipidosis III urinary β-N-acetyl-d-hexosaminidase A were purified to apparent homogeneity by using affinity [Sepharose-2-acetamido-N-(ε-aminocaproyl)-2-deoxy-β- d-glucopyranosylamine] and ion-exchange (DEAE- and CM-cellulose) chromatography. Sodium dodecyl sulphate/polyacrylamide-slab-gel electrophoresis showed that both enzymes had similar subunit patterns consisting of apparent mol.wts. of 68000, 60000–58000, 55000 and 29000. Differences, however, were noted in the relative proportions of the protein bands where the normal urinary β-N-acetyl-d-hexosaminidase A contained predominantly the smaller subunits, whereas the mucolipidosis III enzyme had a predominance of the larger subunits. The binding of mucolipidosis III β-N-acetyl-d-hexosaminidase A to Ricinus communis lectin and concanavalin A with and without endo-β-N-acetyl-d-glucosaminidase H treatment indicated that the mutation leads to a modification of a portion of the normally occurring high-mannose-type oligosaccharide units to the complex-type. This was further supported by carbohydrate compositional analysis, which revealed a mannose/galactose ratio of 2.1 for the mucolipidosis III β-N-acetyl-d-hexosaminidase A compared with a ratio of 3.5 for the normal enzyme. Our results indicate that as a result of their inability to be properly localized to the lysosome the majority of the mucolipidosis III lysosomal hydrolase high-mannose oligosaccharide units are further processed to the complex-type before secretion of predominantly higher-molecular-weight subunits from the cell. ImagesFig. 1. PMID:6219664

  1. Analysis of urinary N-acetyl-beta-D-glucosaminidase using 2,4-dinitrophenyl-1-thio N-acetyl-beta-D-glucosaminide as the substrate.

    PubMed

    Yamada, Magohei; Fujita, Toshio

    2003-01-01

    2,4-Dinitrophenyl-1-thio N-acetyl-beta-D-glucosaminide was examined as a new substrate for analyzing the level of N-acetyl-beta-D-glucosaminidase in the urine of patients suffering from renal diseases. The analysis is based on the fact that the substrate, when hydrolyzed in the presence of N-acetyl-beta-D-glucosaminidase, liberates 2,4-dinitrothiophenol as the chromogen. The optimum pH for the enzyme reaction is 4.6, which is covered by the optimal range for the UV absorbance of the chromogen. The first-order rate of increase of the absorbance at this pH was linear to the enzyme concentration up to 600 U/L, with a high sensitivity. Analytical reagents with glucosaminides of 2,4-dinitrophenol and 2-chloro-4-nitrophenol are less stable than the reagent with glucosaminide of 2,4-dinitrothiophenol. The optimum pH for the absorbance of p-nitrophenol and 2-chloro-4-nitrophenol does not match that for the enzyme reaction. PMID:12784261

  2. Micronutrients, N-Acetyl Cysteine, Probiotics and Prebiotics, a Review of Effectiveness in Reducing HIV Progression

    PubMed Central

    Hummelen, Ruben; Hemsworth, Jaimie; Reid, Gregor

    2010-01-01

    Low serum concentrations of micronutrients, intestinal abnormalities, and an inflammatory state have been associated with HIV progression. These may be ameliorated by micronutrients, N-acetyl cysteine, probiotics, and prebiotics. This review aims to integrate the evidence from clinical trials of these interventions on the progression of HIV. Vitamin B, C, E, and folic acid have been shown to delay the progression of HIV. Supplementation with selenium, N-acetyl cysteine, probiotics, and prebiotics has considerable potential, but the evidence needs to be further substantiated. Vitamin A, iron, and zinc have been associated with adverse effects and caution is warranted for their use. PMID:22254046

  3. Inhibition of the adenine nucleotide translocator by N-acetyl perfluorooctane sulfonamides in vitro

    SciTech Connect

    O'Brien, Timothy M. Oliveira, Paulo J.; Wallace, Kendall B.

    2008-03-01

    N-alkyl perfluorooctane sulfonamides have been widely used as surfactants on fabrics and papers, fire retardants, and anti-corrosion agents, among many other commercial applications. The global distribution and environmental persistence of these compounds has generated considerable interest regarding potential toxic effects. We have previously reported that perfluorooctanesulfonamidoacetate (FOSAA) and N-ethylperfluorooctanesulfonamidoacetate (N-EtFOSAA) induce the mitochondrial permeability transition (MPT) in vitro. In this study we tested the hypothesis that FOSAA and N-EtFOSAA interact with the adenine nucleotide translocator (ANT) resulting in a functional inhibition of the translocator and induction of the MPT. Respiration and membrane potential of freshly isolated liver mitochondria from Sprague-Dawley rats were measured using an oxygen electrode and a tetraphenylphosphonium-selective (TPP{sup +}) electrode, respectively. Mitochondrial swelling was measured spectrophotometrically. The ANT ligands bongkregkic acid (BKA) and carboxyatractyloside (cATR) inhibited uncoupling of mitochondrial respiration caused by 10 {mu}M N-EtFOSAA, 40 {mu}M FOSAA, and the positive control 8 {mu}M oleic acid. ADP-stimulated respiration and depolarization of mitochondrial membrane potential were inhibited by cATR, FOSAA, N-EtFOSAA, and oleic acid, but not by FCCP. BKA inhibited calcium-dependent mitochondrial swelling induced by FOSAA, N-EtFOSAA, and oleic acid. Seventy-five micromolar ADP also inhibited swelling induced by the test compounds, but cATR induced swelling was not inhibited by ADP. Results of this investigation indicate that N-acetyl perfluorooctane sulfonamides interact directly with the ANT to inhibit ADP translocation and induce the MPT, one or both of which may account for the metabolic dysfunction observed in vivo.

  4. Effects of selective inhibition of N-acetylated-alpha-linked-acidic dipeptidase (NAALADase) on mice in learning and memory tasks.

    PubMed

    Lukawski, Krzysztof; Kamiński, Rafał M; Czuczwar, Stanisław J

    2008-01-28

    The purpose of the present study was to examine the effects of 2-(phosphonomethyl)-pentanedioic acid (2-PMPA), a selective inhibitor of N-acetylated-alpha-linked-acidic dipeptidase (NAALADase, glutamate carboxypeptidase II), an enzyme catalyzing the cleavage of glutamate from the neuropeptide N-acetyl-aspartyl-glutamate (NAAG), on memory processes in mice. Long-term memory was evaluated in step-through passive avoidance task while alternation behavior, as a measure involving spatial working memory, was assessed in Y-maze task. Additionally, horizontal activity was evaluated by means of electronically monitored locomotor activity system. The mice were treated with either 2-PMPA (50, 100 and 150 mg/kg i.p.) or N-methyl-d-aspartate (NMDA) receptor antagonist, (5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclo-hepten-5,10-imine hydrogen maleate (MK-801) at doses of: 0.05, 0.1, 0.15 and 0.2 mg/kg i.p., as a comparator. In the passive avoidance task, the drugs were administered once before or immediately after training, and before retention test. 2-PMPA at the doses used did not affect retention of passive avoidance; however, it increased the latency to enter the dark box during the training day. In the Y-maze task, 2-PMPA (150 mg/kg i.p.) impaired spontaneous alternation and reduced locomotion while the lower dose of 100 mg/kg was ineffective. In the locomotor activity test, 2-PMPA (100 and 150 mg/kg i.p.) did not significantly affect horizontal activity. MK-801 (0.2 mg/kg i.p.) injected before training reduced retention in the passive avoidance task. In the Y-maze task, MK-801 (0.1 mg/kg i.p.) impaired alternation behavior and considerably increased locomotion in the Y-maze and locomotor activity test. These results indicate that NAALADase inhibition may impair alternation behavior. PMID:18031726

  5. N-acetyl muramyl dipeptide stimulation of bone resorption in tissue culture.

    PubMed Central

    Dewhirst, F E

    1982-01-01

    N-Acetyl-muramyl-L-alanyl-D-isoglutamine (MDP), a structurally defined fragment of bacterial peptidoglycan, stimulated significant release of previously incorporated 45Ca from fetal rat bones in tissue culture over the concentration range of 0.1 to 10.0 micrograms/ml. MDP-Stimulated bone resorption was not inhibited by the addition of the prostaglandin synthetase inhibitor indomethacin to the culture medium. MDP was neither mitogenic for nor stimulated the release of osteoclast-activating factor from cultured human peripheral blood mononuclear cells. Thus, MDP-stimulated bone resorption in vitro is mediated by a mechanism which is not dependent upon prostaglandins or osteoclast-activating factor. 6-O-Stearoyl-N-acetyl-muramyl-L-alanyl-D-isoglutamine, a lipophilic analog of MDP, was slightly more potent than MDP. Two diastereomers of MDP, N-acetyl-muramyl-L-alanyl-L-isoglutamine and N-acetyl-muramyl-D-alanyl-D-isoglutamine, which are inactive as adjuvants, were at least 1,000 times less active than MDP in stimulating bone resorption. The stereochemical specificity for bone-resorptive activity paralleled that required for adjuvant activity, macrophage activation, and activation of the reticuloendothelial system. PMID:7054120

  6. Identification of the major endogenous leukotriene metabolite in the bile of rats as N-acetyl leukotriene E4

    SciTech Connect

    Hagmann, W.; Denzlinger, C.; Rapp, S.; Weckbecker, G.; Keppler, D.

    1986-02-01

    Mercapturic acid formation, an established pathway in the detoxication of xenobiotics, is demonstrated for cysteinyl leukotrienes generated in rats in vivo after endotoxin treatment. The mercapturate N-acetyl-leukotriene E4 (N-acetyl-LTE4) represented a major metabolite eliminated into bile after injection of (/sup 3/H)LTC4 as shown by cochromatography with synthetic N-acetyl-LTE4 in four different HPLC solvent systems. The identity of endogenous N-acetyl-LTE4 elicited by endotoxin in vivo was additionally verified by enzymatic deacetylation followed by chemical N-acetylation. The deacetylation was catalyzed by penicillin amidase. Endogenous cysteinyl leukotrienes were quantified by radioimmunoassay after HPLC separation. A N-acetyl-LTE4 concentration of 80 nmol/l was determined in bile collected between 30 and 60 min after endotoxin injection. Under this condition, other cysteinyl leukotrienes detected in bile by radioimmunoassay amounted to less than 5% of N-acetyl-LTE4. The mercapturic acid pathway, leading from the glutathione conjugate LTC4 to N-acetyl-LTE4, thus plays an important role in the deactivation and elimination of these potent endogenous mediators.

  7. N-acetylation of three aromatic amine hair dye precursor molecules eliminates their genotoxic potential.

    PubMed

    Zeller, Andreas; Pfuhler, Stefan

    2014-01-01

    N-acetylation has been described as a detoxification reaction for aromatic amines; however, there is only limited data available showing that this metabolic conversion step changes their genotoxicity potential. To extend this database, three aromatic amines, all widely used as precursors in oxidative hair dye formulations, were chosen for this study: p-phenylenediamine (PPD), 2,5-diaminotoluene (DAT) and 4-amino-2-hydroxytoluene (AHT). Aiming at a deeper mechanistic understanding of the interplay between activation and detoxification for this chemical class, we compared the genotoxicity profiles of the parent compounds with those of their N-acetylated metabolites. While PPD, DAT and AHT all show genotoxic potential in vitro, their N-acetylated metabolites completely lack genotoxic potential as shown in the Salmonella typhimurium reversion assay, micronucleus test with cultured human lymphocytes (AHT), chromosome aberration assay with V79 cells (DAT) and Comet assay performed with V79 cells. For the bifunctional aromatic amines studied (PPD and DAT), monoacetylation was sufficient to completely abolish their genotoxic potential. Detoxification through N-acetylation was further confirmed by comparing PPD, DAT and AHT in the Comet assay using standard V79 cells (N-acetyltransferase (NAT) deficient) and two NAT-proficient cell lines,V79NAT1*4 and HaCaT (human keratinocytes). Here we observed a clear shift of dose-response curves towards decreased genotoxicity of the parent aromatic amines in the NAT-proficient cells. These findings suggest that genotoxic effects will only be found at concentrations where the N-acetylation (detoxifying) capacity of the cells is overwhelmed, indicating that a 'first-pass' effect in skin could be taken into account for risk assessment of these topically applied aromatic amines. The findings also indicate that the use of liver S-9 preparations, which generally underestimate Phase II reactions, contributes to the generation of irrelevant

  8. Solution interactions between the uranyl cation [UO2(2+)] and histidine, N-acetyl-histidine, tyrosine, and N-acetyl-tyrosine.

    PubMed

    Xie, Wei; Badawi, Ahmed; Huang, Huan; Van Horn, J David

    2009-01-01

    Complexes of the uranyl cation [UO(2)(2+)] with histidine (His), N-acetyl-histidine (NAH), tyrosine (Tyr), and N-acetyl-tyrosine (NAT) were studied by UV-visible and NMR spectroscopy, and by potentiometric titration. Protonation constants for each ligand are reported, as are cumulative formation constants for uranyl-amino acid complexes. Coupling constant data (J(CH)) for uranyl-histidine complexes indicate that inner-sphere solution interactions between histidine and uranyl cation are solely at the carboxylate site. At 25 degrees C the major uranyl-histidine complex has a cumulative formation constant of logbeta(110)=8.53, and a proposed formula of [UO(2)HisH(2)(OH)(2)](+); the stepwise formation constant, logK(UL), is estimated to be 5.6 ( approximately 8.53-(-6.1)-(-6.1)-15.15). Outer-sphere interactions, H-bonding or electrostatic interactions, are proposed as contributing a significant portion of the stability to the ternary uranyl-hydroxo-amino acid complexes. The temperature dependent protonation constants of histidine and formation constants between uranyl cation and histidine are reported from 10 to 35 degrees C; at 25 degrees C, DeltaG=-43.3 kJ/mol. PMID:18947879

  9. Production of N-Acetyl-d-glucosamine from Mycelial Waste by a Combination of Bacterial Chitinases and an Insect N-Acetyl-d-glucosaminidase.

    PubMed

    Zhu, Weixing; Wang, Di; Liu, Tian; Yang, Qing

    2016-09-01

    N-Acetyl-d-glucosamine (GlcNAc) has great potential to be used as a food additive and medicine. The enzymatic degradation of chitin-containing biomass for producing GlcNAc is an eco-friendly approach but suffers from a high cost. The economical efficiency can be improved by both optimizing the member and ratio of the chitinolytic enzymes and using new inexpensive substrates. To address this, a novel combination of bacterial and insect chitinolytic enzymes was developed in this study to efficiently produce GlcNAc from the mycelia of Asperillus niger, a fermentation waste. This enzyme combination contained three bacterial chitinases (chitinase A from Serratia marcescens (SmChiA), SmChiB, SmChiC) and one insect N-acetyl-d-glucosaminidase from Ostrinia furnacalis (OfHex1) in a ratio of 39.1% of SmChiA, 26.7% of SmChiB, 32.9% of SmChiC, and 1.3% of OfHex1. A yield of 6.3 mM (1.4 mg/mL) GlcNAc with a purity of 95% can be obtained from 10 mg/mL mycelial powder in 24 h. The enzyme combination reported here exhibited 5.8-fold higher hydrolytic activity over the commercial chitinase preparation derived from Streptomyces griseus. PMID:27546481

  10. Inhibition of phagocytic activity by the N-acetyl-D-galactosamine-specific lectin from Amaranthus leucocarpus.

    PubMed

    Maldonado, G; Gorocica, P; Agundis, C; Pérez, A; Molina, J; Zenteno, E

    1998-06-01

    Amaranthus leucocarpus lectin (ALL), specific for N-acetyl-D-galactosamine, induces inhibition of the erythrophagocytic activity of resident murine peritoneal macrophages and of the macrophage-like cell line J-774. This effect was observed only in macrophages that were Mac-2 (CD11c/CD18 or CR4) negative, indicating that macrophage activation induces important modification to the glycosylation (mainly O-glycosylation) of the membrane. Receptors for IgM and C3b remain unaltered after lectin treatment. Ultrastructural analysis revealed (a) that ALL induced the formation of pinocytic vacuoles, and (b) a regular distribution over the macrophage membrane as well as endosomal vesicles of the gold labeled ALL. Our results suggest that macrophage membrane glycoproteins with constitutive N-acetyl-D-galactosamine residues participate in the regulation of pinocytic-phagocytic vacuole formation. PMID:9881768

  11. N-acetyl-L-leucine accelerates vestibular compensation after unilateral labyrinthectomy by action in the cerebellum and thalamus.

    PubMed

    Günther, Lisa; Beck, Roswitha; Xiong, Guoming; Potschka, Heidrun; Jahn, Klaus; Bartenstein, Peter; Brandt, Thomas; Dutia, Mayank; Dieterich, Marianne; Strupp, Michael; la Fougère, Christian; Zwergal, Andreas

    2015-01-01

    An acute unilateral vestibular lesion leads to a vestibular tone imbalance with nystagmus, head roll tilt and postural imbalance. These deficits gradually decrease over days to weeks due to central vestibular compensation (VC). This study investigated the effects of i.v. N-acetyl-DL-leucine, N-acetyl-L-leucine and N-acetyl-D-leucine on VC using behavioural testing and serial [18F]-Fluoro-desoxyglucose ([18F]-FDG)-μPET in a rat model of unilateral chemical labyrinthectomy (UL). Vestibular behavioural testing included measurements of nystagmus, head roll tilt and postural imbalance as well as sequential whole-brain [18F]-FDG-μPET was done before and on days 1,3,7 and 15 after UL. A significant reduction of postural imbalance scores was identified on day 7 in the N-acetyl-DL-leucine (p < 0.03) and the N-acetyl-L-leucine groups (p < 0.01), compared to the sham treatment group, but not in the N-acetyl-D-leucine group (comparison for applied dose of 24 mg i.v. per rat, equivalent to 60 mg/kg body weight, in each group). The course of postural compensation in the DL- and L-group was accelerated by about 6 days relative to controls. The effect of N-acetyl-L-leucine on postural compensation depended on the dose: in contrast to 60 mg/kg, doses of 15 mg/kg and 3.75 mg/kg had no significant effect. N-acetyl-L-leucine did not change the compensation of nystagmus or head roll tilt at any dose. Measurements of the regional cerebral glucose metabolism (rCGM) by means of μPET revealed that only N-acetyl-L-leucine but not N-acetyl-D-leucine caused a significant increase of rCGM in the vestibulocerebellum and a decrease in the posterolateral thalamus and subthalamic region on days 3 and 7. A similar pattern was found when comparing the effect of N-acetyl-L-leucine on rCGM in an UL-group and a sham UL-group without vestibular damage. In conclusion, N-acetyl-L-leucine improves compensation of postural symptoms after UL in a dose-dependent and specific manner, most likely by

  12. N-Acetyl-L-Leucine Accelerates Vestibular Compensation after Unilateral Labyrinthectomy by Action in the Cerebellum and Thalamus

    PubMed Central

    Xiong, Guoming; Potschka, Heidrun; Jahn, Klaus; Bartenstein, Peter; Brandt, Thomas; Dutia, Mayank; Dieterich, Marianne; Strupp, Michael; la Fougère, Christian; Zwergal, Andreas

    2015-01-01

    An acute unilateral vestibular lesion leads to a vestibular tone imbalance with nystagmus, head roll tilt and postural imbalance. These deficits gradually decrease over days to weeks due to central vestibular compensation (VC). This study investigated the effects of i.v. N-acetyl-DL-leucine, N-acetyl-L-leucine and N-acetyl-D-leucine on VC using behavioural testing and serial [18F]-Fluoro-desoxyglucose ([18F]-FDG)-μPET in a rat model of unilateral chemical labyrinthectomy (UL). Vestibular behavioural testing included measurements of nystagmus, head roll tilt and postural imbalance as well as sequential whole-brain [18F]-FDG-μPET was done before and on days 1,3,7 and 15 after UL. A significant reduction of postural imbalance scores was identified on day 7 in the N-acetyl-DL-leucine (p < 0.03) and the N-acetyl-L-leucine groups (p < 0.01), compared to the sham treatment group, but not in the N-acetyl-D-leucine group (comparison for applied dose of 24 mg i.v. per rat, equivalent to 60 mg/kg body weight, in each group). The course of postural compensation in the DL- and L-group was accelerated by about 6 days relative to controls. The effect of N-acetyl-L-leucine on postural compensation depended on the dose: in contrast to 60 mg/kg, doses of 15 mg/kg and 3.75 mg/kg had no significant effect. N-acetyl-L-leucine did not change the compensation of nystagmus or head roll tilt at any dose. Measurements of the regional cerebral glucose metabolism (rCGM) by means of μPET revealed that only N-acetyl-L-leucine but not N-acetyl-D-leucine caused a significant increase of rCGM in the vestibulocerebellum and a decrease in the posterolateral thalamus and subthalamic region on days 3 and 7. A similar pattern was found when comparing the effect of N-acetyl-L-leucine on rCGM in an UL-group and a sham UL-group without vestibular damage. In conclusion, N-acetyl-L-leucine improves compensation of postural symptoms after UL in a dose-dependent and specific manner, most likely by

  13. Kinetics of Mushroom Tyrosinase and Melanogenesis Inhibition by N-Acetyl-pentapeptides

    PubMed Central

    Lien, Ching-Yi; Chen, Ching-Yu; Lai, Shih-Ting

    2014-01-01

    We investigated the kinetics of 4N-acetyl-pentapeptides, Ac-P1, Ac-P2, Ac-P3, and Ac-P4, regarding inhibition of mushroom tyrosinase activity. The peptides sequences of Ac-P1, Ac-P2, Ac-P3, and Ac-P4 were Ac-RSRFK, Ac-KSRFR, Ac-KSSFR, and Ac-RSRFS, respectively. The 4N-acetyl-pentapeptides were able to reduce the oxidation of l-DOPA by tyrosinase in a dose-dependent manner. Of the 4N-acetyl-pentapeptides, only Ac-P4 exhibited lag time (80 s) at a concentration of 0.5 mg/mL. The tyrosinase inhibitory effects of Ac-P4 (IC50 0.29 mg/mL) were more effective than those of Ac-P1, Ac-P2, and Ac-P3, in which IC50s were 0.75 mg/mL, 0.78 mg/mL, and 0.81 mg/mL, respectively. Kinetic analysis demonstrated that all 4N-acetyl-pentapeptides were mixed-type tyrosinase inhibitors. Furthermore, 0.1 mg/mL of Ac-P4 exhibited significant melanogenesis inhibition on B16F10 melanoma cells and was more effective than kojic acid. The melanogenesis inhibition of Ac-P4 was dose-dependent and did not induce any cytotoxicity on B16F10 melanoma cells. PMID:25136665

  14. Inhibition of mucin glycosylation by aryl-N-acetyl-alpha-galactosaminides in human colon cancer cells

    SciTech Connect

    Kuan, S.F.; Byrd, J.C.; Basbaum, C.; Kim, Y.S. )

    1989-11-15

    Specific inhibitors of the glycosylation of O-glycosidically linked glycoproteins have not previously been described. When tested for their effects on mucin glycosylation in a mucin-producing colon cancer cell line, LS174T, benzyl-, phenyl-, and p-nitrophenyl-N-acetyl-alpha-galactosaminide inhibited the formation of fully glycosylated mucin in a dose-dependent manner. Free aryl-oligosaccharides were found in the medium of treated cells labeled with ({sup 3}H)glucosamine, ({sup 3}H)galactose, ({sup 3}H)fucose, ({sup 3}H)mannosamine, or phenyl-alpha-(6-{sup 3}H) N-acetylgalactosamine. UDP-Gal:GalNAc-beta 1,3-galactosyltransferase was inhibited by aryl-N-acetyl-alpha-galactosaminides but not by a number of other aryl-glycosides. Treatment with these inhibitors also causes reversible morphologic changes including formation of intercellular cysts. Aryl-N-acetyl-alpha-galactosaminides can be useful for the structural and functional studies of mucin macromolecules and other O-linked glycoproteins.

  15. N-acetylation and phosphorylation of Sec complex subunits in the ER membrane

    PubMed Central

    2012-01-01

    Background Covalent modifications of proteins provide a mechanism to control protein function. Here, we have investigated modifications of the heptameric Sec complex which is responsible for post-translational protein import into the endoplasmic reticulum (ER). It consists of the Sec61 complex (Sec61p, Sbh1p, Sss1p) which on its own mediates cotranslational protein import into the ER and the Sec63 complex (Sec63p, Sec62p, Sec71p, Sec72p). Little is known about the biogenesis and regulation of individual Sec complex subunits. Results We show that Sbh1p when it is part of the Sec61 complex is phosphorylated on T5 which is flanked by proline residues. The phosphorylation site is conserved in mammalian Sec61ß, but only partially in birds, and not in other vertebrates or unicellular eukaryotes, suggesting convergent evolution. Mutation of T5 to A did not affect the ability of mutant Sbh1p to complement the growth defect in a Δsbh1Δsbh2 strain, and did not result in a hypophosphorylated protein which shows that alternate sites can be used by the T5 kinase. A survey of yeast phosphoproteome data shows that Sbh1p can be phosphorylated on multiple sites which are organized in two patches, one at the N-terminus of its cytosolic domain, the other proximal to the transmembrane domain. Surprisingly, although N-acetylation has been shown to interfere with ER targeting, we found that both Sbh1p and Sec62p are cotranslationally N-acetylated by NatA, and N-acetyl-proteome data indicate that Sec61p is modified by the same enzyme. Mutation of the N-acetylation site, however, did not affect Sec62p function in posttranslational protein import into the ER. Disabling NatA resulted in growth retardation, but not in co- or posttranslational translocation defects or instability of Sec62p or Sbh1p. Conclusions We conclude that N-acetylation of transmembrane and tail-anchored proteins does not interfere with their ER-targeting, and that Sbh1p phosphorylation on T5, which is not present in

  16. A single mutation in the active site swaps the substrate specificity of N-acetyl-L-ornithine transcarbamylase and N-succinyl-L-ornithine transcarbamylase

    PubMed Central

    Shi, Dashuang; Yu, Xiaolin; Cabrera-Luque, Juan; Chen, Tony Y.; Roth, Lauren; Morizono, Hiroki; Allewell, Norma M.; Tuchman, Mendel

    2007-01-01

    Transcarbamylases catalyze the transfer of the carbamyl group from carbamyl phosphate (CP) to an amino group of a second substrate such as aspartate, ornithine, or putrescine. Previously, structural determination of a transcarbamylase from Xanthomonas campestris led to the discovery of a novel N-acetylornithine transcarbamylase (AOTCase) that catalyzes the carbamylation of N-acetylornithine. Recently, a novel N-succinylornithine transcarbamylase (SOTCase) from Bacteroides fragilis was identified. Structural comparisons of AOTCase from X. campestris and SOTCase from B. fragilis revealed that residue Glu92 (X. campestris numbering) plays a critical role in distinguishing AOTCase from SOTCase. Enzymatic assays of E92P, E92S, E92V, and E92A mutants of AOTCase demonstrate that each of these mutations converts the AOTCase to an SOTCase. Similarly, the P90E mutation in B. fragilis SOTCase (equivalent to E92 in X. campestris AOTCase) converts the SOTCase to AOTCase. Hence, a single amino acid substitution is sufficient to swap the substrate specificities of AOTCase and SOTCase. X-ray crystal structures of these mutants in complexes with CP and N-acetyl-L-norvaline (an analog of N-acetyl-L-ornithine) or N-succinyl-L-norvaline (an analog of N-succinyl-L-ornithine) substantiate this conversion. In addition to Glu92 (X. campestris numbering), other residues such as Asn185 and Lys30 in AOTCase, which are involved in binding substrates through bridging water molecules, help to define the substrate specificity of AOTCase. These results provide the correct annotation (AOTCase or SOTCase) for a set of the transcarbamylase-like proteins that have been erroneously annotated as ornithine transcarbamylase (OTCase, EC 2.1.3.3). PMID:17600144

  17. Activation of the aryl hydrocarbon receptor by carcinogenic aromatic amines and modulatory effects of their N-acetylated metabolites.

    PubMed

    Juricek, Ludmila; Bui, Linh-Chi; Busi, Florent; Pierre, Stéphane; Guyot, Erwan; Lamouri, Aazdine; Dupret, Jean-Marie; Barouki, Robert; Coumoul, Xavier; Rodrigues-Lima, Fernando

    2015-12-01

    Aromatic amines (AAs) are an important class of chemicals which account for 12 % of known carcinogens. The biological effects of AAs depend mainly on their biotransformation into reactive metabolites or into N-acetylated metabolites which are generally considered as less toxic. Although the activation of the aryl hydrocarbon receptor (AhR) pathway by certain carcinogenic AAs has been reported, the effects of their N-acetylated metabolites on the AhR have not been addressed. Here, we investigated whether carcinogenic AAs and their N-acetylated metabolites may activate/modulate the AhR pathway in the absence and/or the presence of a bona fide AhR ligand (benzo[a]pyrene/B(a)P]. In agreement with previous studies, we found that certain AAs activated the AhR in human liver and lung cells as assessed by an increase in cytochrome P450 1A1 (CYP1A1) expression and activity. Altogether, we report for the first time that these properties can be modulated by the N-acetylation status of the AA. Whereas 2-naphthylamine significantly activated the AhR and induced CYP1A1 expression, its N-acetylated metabolite was less efficient. In contrast, the N-acetylated metabolite of 2-aminofluorene was able to significantly activate AhR, whereas the parent AA, 2-aminofluorene, did not. In the presence of B(a)P, activation of AhR or antagonist effects were observed depending on the AA or its N-acetylated metabolite. Activation and/or modulation of the AhR pathway by AAs and their N-acetylated metabolites may represent a novel mechanism contributing to the toxicological effects of AAs. More broadly, our data suggest biological interactions between AAs and other classes of xenobiotics through the AhR pathway. PMID:25224404

  18. Interactions between N-acetyl-L-cysteine protected CdTe quantum dots and doxorubicin through spectroscopic method

    SciTech Connect

    Yang, Xiupei; Lin, Jia; Liao, Xiulin; Zong, Yingying; Gao, Huanhuan

    2015-06-15

    Highlights: • CdTe quantum dots with the diameter of 3–5 nm were synthesized in aqueous solution. • The modified CdTe quantum dots showed well fluorescence properties. • The interaction between the CdTe quantum dots and doxorubicin (DR) was investigated. - Abstract: N-acetyl-L-cysteine protected cadmium telluride quantum dots with a diameter of 3–5 nm were synthesized in aqueous solution. The interaction between N-acetyl-L-cysteine/cadmium telluride quantum dots and doxorubicin was investigated by ultraviolet–visible absorption and fluorescence spectroscopy at physiological conditions (pH 7.2, 37 °C). The results indicate that electron transfer has occurred between N-acetyl-L-cysteine/cadmium telluride quantum dots and doxorubicin under light illumination. The quantum dots react readily with doxorubicin to form a N-acetyl-L-cysteine/cadmium telluride-quantum dots/doxorubicin complex via electrostatic attraction between the −NH{sub 3}{sup +} moiety of doxorubicin and the −COO{sup −} moiety of N-acetyl-L-cysteine/cadmium telluride quantum dots. The interaction of N-acetyl-L-cysteine/cadmium telluride-quantum dots/doxorubicin complex with bovine serum albumin was studied as well, showing that the complex might induce the conformation change of bovine serum due to changes in microenvironment of bovine serum.

  19. A conformational study of N -acetyl glucosamine derivatives utilizing residual dipolar couplings

    NASA Astrophysics Data System (ADS)

    Kramer, Markus; Kleinpeter, Erich

    2011-09-01

    The conformational analyses of six non-rigid N-acetyl glucosamine (NAG) derivatives employing residual dipolar couplings (RDCs) and NOEs together with molecular dynamics (MD) simulations are presented. Due to internal dynamics we had to consider different conformer ratios existing in solution. The good quality of the correlation between theoretically and experimentally obtained RDCs show the correctness of the calculated conformers even if the ratios derived from the MD simulations do not exactly meet the experimental data. If possible, the results were compared to former published data and commented.

  20. N-Acetyl-5-chloro-3-nitro-l-tyrosine ethyl ester

    PubMed Central

    Mutahi, Teresa T.; Edagwa, Benson J.; Fronczek, Frank R.; Uppu, Rao M.

    2012-01-01

    The title compound, C13H15ClN2O6, was synthesized by hypochlorous acid-mediated chlorination of N-acetyl-3-nitro-l-tyrosine ethyl ester. The OH group forms an intra­molecular O—H⋯O hydrogen bond to the nitro group and the N—H group forms an inter­molecular N—H⋯O hydrogen bonds to an amide O atom, linking the mol­ecules into chains along [100]. The crystal studied was a non-merohedral twin, with a 0.907 (4):0.093 (4) domain ratio. PMID:22969682

  1. N-Acetyl glycals are tight-binding and environmentally insensitive inhibitors of hexosaminidases.

    PubMed

    Santana, A G; Vadlamani, G; Mark, B L; Withers, S G

    2016-06-28

    Mono-, di- and trisaccharide derivatives of 1,2-unsaturated N-acetyl-d-glucal have been synthesized and shown to function as tight-binding inhibitors/slow substrates of representative hexosaminidases. Turnover is slow and not observed in the thioamide analogue, allowing determination of the 3-dimensional structure of the complex. Inhibition is insensitive to pH and to mutation of key catalytic residues, consistent with the uncharged character of the inhibitor. These properties could render this inhibitor class less prone to development of resistance. PMID:27253678

  2. Chemoenzymatic synthesis of CMP-N-acetyl-7-fluoro-7-deoxy-neuraminic acid.

    PubMed

    Hartlieb, Sina; Günzel, Almut; Gerardy-Schahn, Rita; Münster-Kühnel, Anja K; Kirschning, Andreas; Dräger, Gerald

    2008-08-11

    7-Fluoro sialic acid was prepared and activated as cytidine monophosphate (CMP) ester. The synthesis started with d-glucose, which was efficiently converted into N-acetyl-4-fluoro-4-deoxy-d-mannosamine. Aldolase catalyzed transformation yielded the corresponding fluorinated sialic acid which was activated as CMP ester using three different synthetases in the presence as well as in the absence of pyrophosphatase which possesses inhibitory properties. Finally, conditions were optimized to perform a one-pot reaction starting from fluorinated mannosamine, which yielded the 7-fluoro-7-deoxy-CMP-sialic acid by incubation with three enzymes. PMID:18353292

  3. Urinary mutagenicity and N-acetylation phenotype in textile industry workers exposed to arylamines

    SciTech Connect

    Sinues, B.; Perez, J.; Bernal, M.L.; Saenz, M.A.; Lanuza, J.; Bartolome, M. )

    1992-09-15

    Primary aromatic amines have been identified epidemiologically as human carcinogens. It has been suggested that the target organ affected by aromatic amines is dependent on the rate of metabolic activation. Epidemiological studies have shown an association between low acetyl transferase activity and bladder cancer risk. On this basis, our working hypothesis was that the slow acetylators could follow in a higher extent the metabolic pathway independent of N-acetylation, leading to the excretion of conjugates of electrophyles with glucuronic acid. The instability of these glucuronides could be responsible for the association between arylamine-induced bladder cancer and slow acetylator phenotype. A total of 153 individuals were included in this study: 70 exposed to arylamines (working in textile industry) and 83 nonexposed. The following parameters were determined in urine: mutagenic index in the absence of metabolic activation, S9; mutagenic index in the presence of S9; and the mutagenic index after incubation of the urine with beta-glucuronidase. All individuals were phenotyped according to their capacity of N-acetylation by using isoniazid as drug test. The results show that the mutagenic index after incubation of the urine with beta-glucuronidase is statistically higher in exposed subjects when compared with nonexposed individuals (P less than 0.001), this parameter being statistically higher among exposed subjects who were slow acetylators than among rapid metabolizers, independent of the fact that they were smokers or nonsmokers. There were no significant differences between groups for the mutagenicity in urine not incubated with beta-glucuronidase.

  4. Interactions of egg yolk phosphatidylcholine with cholesteryl polyethoxy neoglycolipids containing N-acetyl- D-glucosamine

    NASA Astrophysics Data System (ADS)

    Kemoun, Rachida; Gelhausen, Micaèle; Besson, Françoise; Lafont, Dominique; Buchet, René; Boullanger, Paul; Roux, Bernard

    1999-03-01

    Series of neoglycolipids containing cholesteryl and N-acetyl- D-glucosaminyl groups were synthesized with various ethoxy linkers. Their self aggregations and intermolecular interactions, without and with egg yolk phosphatidylcholine (EYPC), were characterized in dry and hydrated states, by using infrared spectroscopy. The neoglycolipids in the dry state formed intermolecular hydrogen bonds between the CO and N-H or O-H groups of N-acetyl- D-glucosamine (GlcNAc). In the presence of EYPC, these intermolecular interactions were broken and new hydrogen bonds, involving the phosphate group of EYPC and N-H or O-H groups of GlcNAc of neoglycolipid, were formed. The presence of water molecules altered these intermolecular hydrogen bonds. The CO groups of EYPC were not affected by the presence of neoglycolipids, either in hydrated or in dry states, indicating that the GlcNAc polar groups interacted mostly with EYPC phosphate residues. The phase transition-temperature of mixtures of EYPC containing either cholesterol or neoglycolipid were similar, indicating that the cholesteryl group of the neoglycolipid interacted in the same manner as cholesterol with hydrocarbon chains of EYPC. Some structural models of molecular interactions of neoglycolipids were discussed in relation with the molecular recognition of wheat germ agglutinin.

  5. N-acetylation of aromatic amines: implication for skin and immune cells.

    PubMed

    Bonifas, Jutta; Blomeke, Brunhilde

    2015-01-01

    Frequently, aromatic amine (AA) contact to the skin occurs via occupational or 'life style' exposure to hair dye intermediates and couplers, usually monocyclic p-phenylenediamines and meta-substituted aminophenols. The transport of AA from the outer surface to the systemic circulation predominantly follows the intracellular route. Skin tends to have relatively higher phase II compared to phase I xenobiotic metabolizing enzyme capacity, and levels are generally regarded as lower than those in liver. Inside skin cells AA are primarily N-acetylated and detoxified by N-acetyltransferase 1. AA activation via hydroxylation or chemical oxidation competes with acetylation and is only of importance under circumstances when N-acetylation capacities are limited. The reactive AA derivatives are able to elicit effects by virtue of their modifications of skin proteins resulting in irritant or allergic contact dermatitis. Overall, the effective acetylation of topically applied AAs in skin cells emphasizes a protective role of cutaneous acetylation mediating a classical "first-pass" effect, which attenuates systemic exposure. PMID:25553379

  6. Reversible Post-Translational Carboxylation Modulates The Enzymatic Activity Of N-Acetyl-L-Ornithine Transcarbamylase†

    PubMed Central

    Li, Yongdong; Yu, Xiaolin; Ho, Jeremy; Fushman, David; Allewell, Norma M.; Tuchman, Mendel; Shi, Dashuang

    2010-01-01

    N-acetyl-L-ornithine transcarbamylase (AOTCase), rather than ornithine transcarbamylase (OTCase), is the essential carbamylase enzyme in the arginine biosynthesis of several plant and human pathogens. The specificity of this unique enzyme provides a potential target for controlling the spread of these pathogens. Recently, several crystal structures of AOTCase from Xanthomonas campestris (xc) have been determined. In these structures, an unexplained electron density at the tip of Lys302 side-chain was observed. Using 13C NMR spectroscopy, we show herein that Lys302 is post-translationally carboxylated. The structure of wild-type AOTCase complexed with the bisubstrate analogue, Nδ-(phosphonoacetyl)-Nα-acetyl-L-ornithine (PALAO), indicates that the carboxyl group on Lys302 forms a strong hydrogen bonding network with surrounding active site residues, Lys252, Ser253, His293, and Glu92 from the adjacent subunit either directly or via a water molecule. Furthermore, the carboxyl group is involved in binding N-acetyl-L-ornithine via a water molecule. Activity assays with the wild-type enzyme and several mutants demonstrate that the post translational modification of lysine 302 has an important role in catalysis. PMID:20695527

  7. [Separation and properties of N-acetyl-beta-D-glucosaminidase from human seminal plasma].

    PubMed

    Yoshida, K; Uchijima, Y; Kobayashi, N; Saitoh, H

    1989-11-01

    N-acetyl-beta-D-glucosaminidase from human seminal plasma has been separated by the cellulose acetate electrophoresis into two components, isoenzyme I and II. The two isoenzymes are readily separated on a DEAE-Sephadex column. Isoenzyme I which has adsorbed to the column, is eluted at 0.1 M NaCl, whereas isoenzyme II has passed through the column. The following enzyme properties have been obtained: 1) Both isoenzymes show the same Km values (0.27 X 10(-3) M) towards sodio-m-cresol-sufonphtaleinyl-N-acetyl-beta-D-glucosaminide . 2) Both isoenzymes show the same pH optima of 5.4. 3) Optimal temperature for isoenzyme I is 50 degrees C, while that for isoenzyme II is 65 degrees C. Isoenzyme II is heat stable, while isoenzyme I is easily denatured by heat. These characteristics of isoenzyme I and II coincide with previous reports of NAG A and B from the spleen and the kidney, respectively. The activity ratio of isoenzyme I and II has been studied for the reproductive tissues. The % ratio of isoenzyme I and II in the epididymal head is 62 and 38, that in the epididymal tail is 42 and 58, and 38:62 in the seminal vesicle, 35:65 in the prostatic gland and 27:73 in the seminal plasma. PMID:2593437

  8. Infrared and Raman spectra of N-acetyl- L-amino acid methylamides with aromatic side groups

    NASA Astrophysics Data System (ADS)

    Matsuura, Hiroatsu; Hasegawa, Kodo; Miyazawa, Tatsuo

    Infrared and Raman spectra of N-acetyl- L-phenylalanine methylamide, N-acetyl- L-tyrosine methylamide and N-acetyl- L-tryptophan methylamide, as model compounds of aromatic amino acid residues in proteins, were measured in the solid state and in methanol solutions. Vibrational assignments of the spectra were made by utilizing the deuteration effect and by comparison with the spectra of related compounds which include toluene, p-cresol and 3-methylindole. The amide I, III and IV bands were strong in Raman scattering, but other characteristic amide bands were ill-defined. In the Raman spectra of methanol solutions, only the bands due to the aromatic side group vibrations were markedly observed, but those due to the peptide backbone vibrations were very weak, suggesting the coexistence of various molecular conformations in solution.

  9. Concurrent esterification and N-acetylation of amino acids with orthoesters: A useful reaction with interesting mechanistic implications.

    PubMed

    Gibson, Sarah; Romero, Dickie; Jacobs, Hollie K; Gopalan, Aravamudan S

    2010-12-22

    The concurrent esterification and N-acetylation of amino acids has been studied with triethyl orthoacetate (TEOA) and triethyl orthoformate (TEOF). In a surprising finding, only one equivalent of TEOA in refluxing toluene was necessary to convert L-proline and L-phenylalanine to the corresponding N-acetyl ethyl esters in good yield. The same transformation using TEOF was not effective. Stereochemical outcome and stoichiometric studies as well as structural variation of the amino acids in this reaction provided unexpected mechanistic insight. PMID:21286246

  10. Concurrent esterification and N-acetylation of amino acids with orthoesters: A useful reaction with interesting mechanistic implications

    PubMed Central

    Gibson, Sarah; Romero, Dickie; Jacobs, Hollie K.; Gopalan, Aravamudan S.

    2010-01-01

    The concurrent esterification and N-acetylation of amino acids has been studied with triethyl orthoacetate (TEOA) and triethyl orthoformate (TEOF). In a surprising finding, only one equivalent of TEOA in refluxing toluene was necessary to convert L-proline and L-phenylalanine to the corresponding N-acetyl ethyl esters in good yield. The same transformation using TEOF was not effective. Stereochemical outcome and stoichiometric studies as well as structural variation of the amino acids in this reaction provided unexpected mechanistic insight. PMID:21286246

  11. Influence of environmental conditions on hyphal morphology in pellets of Aspergillus niger: role of beta-N-acetyl-D-glucosaminidase.

    PubMed

    Pera, L M; Baigorí, M D; Callieri, D

    1999-08-01

    The influence of modifications of the environmental conditions of growth on beta-N-acetyl-D-glucosaminidase (EC 3.2.1.30) activity and on hyphal morphological patterns in pellets of Aspergillus niger was studied. It was found that changes in the degree of branching and, to a lesser extent, in the number of bulbous cells were directly related to the activity of the enzyme. Nevertheless, since beta-N-acetyl-D-glucosaminidase is not the only enzyme involved in the lytic potential of the fungus, these findings do not exclude the possibility that other enzymes may be involved. PMID:10398828

  12. Bioanalysis of N-acetyl-aspartyl-glutamate as a marker of glutamate carboxypeptidase II inhibition.

    PubMed

    Thomas, Ajit G; Rojas, Camilo J; Hill, Jeanette R; Shaw, Michael; Slusher, Barbara S

    2010-09-01

    We report the characterization of two methods for the analysis of N-acetyl-aspartyl-glutamate (NAAG) in biological fluids. In the first method, NAAG concentrations were calculated based on differences between glutamate concentrations before and after NAAG hydrolysis with exogenous glutamate carboxypeptidase II (GCP II) using high-performance liquid chromatography (HPLC) followed by fluorescence detection. In the second method, NAAG levels were quantified directly using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Analyses of NAAG levels in human cerebrospinal fluid samples using either method gave similar results within experimental error, confirming the validity of the two independent measurements. These methods will be useful in future clinical trials to assess drug-induced GCP II inhibition in biological matrices. PMID:20434427

  13. Metabolomic Analysis of Blood Plasma after Oral Administration of N-acetyl-d-Glucosamine in Dogs.

    PubMed

    Osaki, Tomohiro; Kurozumi, Seiji; Sato, Kimihiko; Terashi, Taro; Azuma, Kazuo; Murahata, Yusuke; Tsuka, Takeshi; Ito, Norihiko; Imagawa, Tomohiro; Minami, Saburo; Okamoto, Yoshiharu

    2015-08-01

    N-acetyl-d-glucosamine (GlcNAc) is a monosaccharide that polymerizes linearly through (1,4)-β-linkages. GlcNAc is the monomeric unit of the polymer chitin. GlcNAc is a basic component of hyaluronic acid and keratin sulfate found on the cell surface. The aim of this study was to examine amino acid metabolism after oral GlcNAc administration in dogs. Results showed that plasma levels of ectoine were significantly higher after oral administration of GlcNAc than prior to administration (p < 0.001). To our knowledge, there have been no reports of increased ectoine concentrations in the plasma. The mechanism by which GlcNAc administration leads to increased ectoine plasma concentration remains unclear; future studies are required to clarify this mechanism. PMID:26262626

  14. Effect of N-acetyl-D-glucosamine on gene expression in Vibrio parahaemolyticus.

    PubMed

    Thompson, Fabiano L; Neto, Antonio Alves; Santos, Eidy de O; Izutsu, Kaori; Iida, Tetsuya

    2011-01-01

    We analyzed the effect of N-acetyl-D-glucosamine (GlcNAc) on gene expression in the marine bacterium Vibrio parahaemolyticus. The total number of genes whose expression was induced and repressed genes in the presence of GlcNAc was 81 and 55, respectively. The induced genes encoded a variety of products, including proteins related to energy metabolism (e.g. GlcNAc and chitin utilization), transport, central metabolism and chemotaxis, hypothetical proteins, mannose-sensitive hemagglutinin pilus (MSHA), and a PilA protein, whereas the repressed genes encoded mainly hypothetical proteins. GlcNAc appears to influence directly or indirectly a variety of cellular processes, including energy metabolism, chitin utilization, competence, biofilm formation and pathogenicity. GlcNAc, one of the most abundant aminosugars in the oceans, is used by V. parahaemolyticus as an energy source and affects the cellular functioning of this marine bacterium. PMID:21487204

  15. Metabolite regulation of the interaction between Arabidopsis thaliana PII and N-acetyl-l-glutamate kinase.

    PubMed

    Feria Bourrellier, Ana Belén; Ferrario-Méry, Sylvie; Vidal, Jean; Hodges, Michael

    2009-10-01

    The metabolic control of the interaction between ArabidopsisN-acetyl-l-glutamate kinase (NAGK) and the PII protein has been studied. Both gel exclusion and affinity chromatography analyses of recombinant, affinity-purified PII (trimeric complex) and NAGK (hexameric complex) showed that NAGK strongly interacted with PII only in the presence of Mg-ATP, and that this process was reversed by 2-oxoglutarate (2-OG). Furthermore, metabolites such as arginine, glutamate, citrate, and oxalacetate also exerted a negative effect on the PII-NAGK complex formation in the presence of Mg-ATP. Using chloroplast protein extracts and PII affinity chromatography, NAGK interacted with PII only in the presence of ATP-Mg(2+), and this process was antagonized by 2-OG. These results reveal a complex metabolic control of the PII interaction with NAGK in the chloroplast stroma of higher plants. PMID:19631611

  16. Glucosamine and N-acetyl glucosamine as new CEST MRI agents for molecular imaging of tumors

    PubMed Central

    Rivlin, Michal; Navon, Gil

    2016-01-01

    The efficacy of glucosamine (GlcN) and N-acetyl glucosamine (GlcNAc) as agents for chemical exchange saturation transfer (CEST) magnetic resonance molecular imaging of tumors is demonstrated. Both agents reflect the metabolic activity and malignancy of the tumors. The method was tested in two types of tumors implanted orthotopically in mice: 4T1 (mouse mammary cancer cells) and MCF7 (human mammary cancer cells). 4T1 is a more aggressive type of tumor than MCF7 and exhibited a larger CEST effect. Two methods of administration of the agents, intravenous (IV) and oral (PO), gave similar results. The CEST MRI observation of lung metastasis was confirmed by histology. The potential of the clinical application of CEST MRI with these agents for cancer diagnosis is strengthened by their lack of toxicity as can be indicated from their wide use as food supplements. PMID:27600054

  17. Glucosamine and N-acetyl glucosamine as new CEST MRI agents for molecular imaging of tumors.

    PubMed

    Rivlin, Michal; Navon, Gil

    2016-01-01

    The efficacy of glucosamine (GlcN) and N-acetyl glucosamine (GlcNAc) as agents for chemical exchange saturation transfer (CEST) magnetic resonance molecular imaging of tumors is demonstrated. Both agents reflect the metabolic activity and malignancy of the tumors. The method was tested in two types of tumors implanted orthotopically in mice: 4T1 (mouse mammary cancer cells) and MCF7 (human mammary cancer cells). 4T1 is a more aggressive type of tumor than MCF7 and exhibited a larger CEST effect. Two methods of administration of the agents, intravenous (IV) and oral (PO), gave similar results. The CEST MRI observation of lung metastasis was confirmed by histology. The potential of the clinical application of CEST MRI with these agents for cancer diagnosis is strengthened by their lack of toxicity as can be indicated from their wide use as food supplements. PMID:27600054

  18. Neuroprotection in rabbit retina with N-acetyl-aspartylglutamate and 2-phosphonyl-methyl pentanedioic acid

    NASA Astrophysics Data System (ADS)

    Hacker, Henry D.; Yourick, Debra L.; Koenig, Michael K.; Slusher, Barbara S.; Meyerhoff, James L.

    1999-06-01

    Retinal tissue is subject to ischemia from diabetic retinopathy and other conditions that affect the retinal vasculature such as lupus erythematosus and temporal arteritis. There is evidence in animal models of reversible ischemia that a therapeutic window exists during early recovery when agents that reduce glutamate activity at its receptor sites can rescue neurons from injury. To model ischemia, we used sodium cyanide (NaCN), to inhibit oxidative metabolism, and 2-deoxyglucose (2-DG) to inhibit glycolysis. Dissociated rabbit retina cells were studied to evaluate the potential neuroprotective effects of N-acetyl-aspartyl-glutamate (MAAG), which competes with glutamate as a low-potency agonist at the NMDA receptor complex. N-acetylated α-linked acidic dipeptidase (NAALADase; the NAAG-hydrolyzing enzyme) is responsible for the hydrolysis of NAAG into glutamate, a neurotransmitter and potent excitotoxin, and N-acetylaspartate. 2-Phosphonyl-methyl pentanedioic acid (PMPA) and β-linked NAAG (β-NAAG), inhibitors of NAALADase, were also tested, since inhibition of NAALADase could reduce synaptic glutamate and increase the concentration of NAAG. We found that metabolic inhibition with NaCN/2-DG for 1 hour caused 50% toxicity as assessed with the MTT assay. Co-treatment with NAAG resulted in dose-dependent protection of up to 55% (p<0.005). When the non-hydrolyzable, NAALADase inhibitor β-NAAG was employed dose-dependent protection of up to 37% was observed (p<0.001). PMPA also showed 48% protection (p<.05-.001) against these insults. These data suggest that NAAG may antagonize the effect of glutamate at the NMDA receptor complex in retina. Inhibition of NAALADase by PMPA and β-NAAG may increase the activity of endogenous NAAG.

  19. Differential Neuroprotective Effects of Carnosine, Anserine, and N-Acetyl Carnosine against Permanent Focal Ischemia

    PubMed Central

    Min, Jiangyong; Senut, Marie-Claude; Rajanikant, Krishnamurthy; Greenberg, Eric; Bandagi, Ram; Zemke, Daniel; Mousa, Ahmad; Kassab, Mounzer; Farooq, Muhammad U.; Gupta, Rishi; Majid, Arshad

    2009-01-01

    Carnosine (β-alanyl-L-histidine) has been shown to exhibit neuroprotection in rodent models of cerebral ischemia. In the present study, we further characterized the effects of carnosine treatment in a mouse model of permanent focal cerebral ischemia and compared them with its related peptides anserine and N-acetylated carnosine. We also evaluated the efficacy of bestatin, a carnosinase inhibitor, in ameliorating ischemic brain damage. Permanent focal cerebral ischemia was induced by occlusion of the middle cerebral artery (pMCAO). Mice were subsequently randomly assigned to receive an intraperitoneal injection of vehicle (0.9% saline), carnosine, N-acetyl carnosine, anserine, bestatin alone, or bestatin with carnosine. Infarct size was examined using 2,3,5-triphenyltetrazolium chloride staining 1, 3, and 7 days following pMCAO, and neurological function was evaluated using an 18-point-based scale. Brain levels of carnosine were measured in treated mice using high-performance liquid chromatography 1 day following pMCAO. We demonstrated that treatment with carnosine, but not its analogues, was able to significantly reduce infarct volume and improve neurological function compared with those in vehicle-treated mice. These beneficial effects were maintained for 7 days post-pMCAO. In contrast, compared with the vehicle-treated group, bestatin-treated mice displayed an increase in the severity of ischemic lesion, which was prevented by the addition of carnosine. These new data further characterize the neuroprotective effects of carnosine and suggest that carnosine may be an attractive candidate for testing as a stroke therapy. PMID:18543335

  20. Effect of arylamine acetyltransferase Nat3 gene knockout on N-acetylation in the mouse.

    PubMed

    Sugamori, K S; Brenneman, D; Wong, S; Gaedigk, A; Yu, V; Abramovici, H; Rozmahel, R; Grant, D M

    2007-07-01

    Arylamine N-acetyltransferases (NAT) catalyze the biotransformation of many important arylamine drugs and procarcinogens. NAT can either detoxify or activate procarcinogens, complicating the manner in which these enzymes may participate in enhancing or preventing toxic responses to particular agents. Mice possess three NAT isoenzymes: Nat1, Nat2, and Nat3. Whereas Nat1 and Nat2 can efficiently acetylate many arylamines, few substrates appear to be appreciably metabolized by Nat3. We generated a Nat3 knockout mouse strain and used it along with our double Nat1/2(-/-) knockout strain to further investigate the functional role of Nat3. Nat3(-/-) mice showed normal viability and reproductive capacity. Nat3 expression was very low in wild-type animals and completely undetectable in Nat3(-/-) mice. In contrast, greatly elevated expression of Nat3 transcript was observed in Nat1/2(-/-) mice. We used a transcribed marker polymorphism approach to establish that the increased expression of Nat3 in Nat1/2(-/-) mice is a positional artifact of insertion of the phosphoglycerate kinase-neomycin resistance cassette in place of the Nat1/Nat2 gene region and upstream of the intact Nat3 gene, rather than a biological compensatory mechanism. Despite the increase in Nat3 transcript, the N-acetylation of p-aminosalicylate, sulfamethazine, 2-aminofluorene, and 4-aminobiphenyl was undetectable either in vivo or in vitro in Nat1/2(-/-) animals. In parallel, no difference was observed in the in vivo clearance or in vitro metabolism of any of these substrates between wild-type and Nat3(-/-) mice. Thus, Nat3 is unlikely to play a significant role in the N-acetylation of arylamines either in wild-type mice or in mice lacking Nat1 and Nat2 activities. PMID:17403913

  1. Pharmacokinetics and N-acetylation metabolism of S-methyl-l-cysteine and trans-S-1-propenyl-l-cysteine in rats and dogs.

    PubMed

    Amano, Hirotaka; Kazamori, Daichi; Itoh, Kenji

    2016-11-01

    1. Pharmacokinetics and N-acetylation metabolism of S-methyl-L-cysteine (SMC) and trans-S-1-propenyl-L-cysteine (S1PC) were examined in rats and dogs. SMC and S1PC (2-5 mg/kg) were well absorbed in both species with high bioavailability (88-100%). 2. SMC and S1PC were excreted only to a small extent in the urine of rats and dogs. The small renal clearance values (<0.03 l/h/kg) indicated the extensive renal reabsorption of SMC and S1PC, which potentially contributed to their long elimination half-lives (>5 h) in dogs. 3. S1PC, but not SMC, underwent N-acetylation extensively in vivo, which can be explained by the relative activities of N-acetylation of S1PC/SMC and deacetylation of their N-acetylated forms, N-acetyl-S1PC/N-acetyl-SMC, in the liver and kidney in vitro. The activities for S1PC N-acetylation were similar to or higher than those for N-acetyl-S1PC deacetylation in liver S9 fractions of rat and dog, whereas liver and kidney S9 fractions of rat and dog had little activity for SMC N-acetylation or considerably higher activities for N-acetyl-SMC deacetylation. 4. Our study demonstrated that the pharmacokinetics of SMC and S1PC in rats and dogs was characterized by high bioavailability and extensive renal reabsorption; however, the extent of undergoing the N-acetylation metabolism was extremely different between SMC and S1PC. PMID:26887651

  2. Computational Study of Environmental Effects on Torsional Free Energy Surface of N-Acetyl-N'-methyl-L-alanylamide Dipeptide

    ERIC Educational Resources Information Center

    Carlotto, Silvia; Zerbetto, Mirco

    2014-01-01

    We propose an articulated computational experiment in which both quantum mechanics (QM) and molecular mechanics (MM) methods are employed to investigate environment effects on the free energy surface for the backbone dihedral angles rotation of the small dipeptide N-Acetyl-N'-methyl-L-alanylamide. This computation exercise is appropriate for an…

  3. Effects of N-acetyl-L-cysteine and glutathione on antioxidant status of human serum and 3T3 fibroblasts.

    PubMed Central

    Hong, Sae-Yong; Yang, Jong-Oh; Lee, Eun-Young; Lee, Zee-Won

    2003-01-01

    The effectiveness of several sulfhydryl compounds in the treatment of paraquat intoxication has been previously tested based on their antioxidant ability. However, practical guidelines for their clinical use remain to be determined. As a preliminary pharmacokinetic study on sulfhydryl compounds, we attempted to establish the optimal concentration of N-acetyl-L-cysteine, glutathione, superoxide dismutase, and catalase. We measured the antioxidant effect of these antioxidants in normal pooled plasma and on intracellular reactive oxygen species (ROS) induced by paraquat. N-acetyl-L-cysteine begins to suppress the production of ROS in plasma at concentrations as low as 5 mM, with the suppression being maximal at 40 mM. In the same way, glutathione increased the total antioxidant status in plasma at concentrations of 5-40 mM in a dose-dependent manner. Complete suppression of ROS in plasma induced by exposure to 500 micro M paraquat for 40 min was observed when using 40 mM N-acetyl-L-cysteine and 5 mM glutathione. These concentrations are comparable with 50 units of catalase, which reduced ROS at concentrations of 5-100 units. Further pharmacokinetic study into the systemic administration of these antioxidants is necessary, using effective concentrations of 5-40 mM for both N-acetyl-L-cysteine and glutathione, and 1-50 units of catalase. PMID:14555815

  4. NagA-Dependent Uptake of N-Acetyl-Glucosamine and N-Acetyl-Chitin Oligosaccharides across the Outer Membrane of Caulobacter crescentus▿

    PubMed Central

    Eisenbeis, Simone; Lohmiller, Stefanie; Valdebenito, Marianne; Leicht, Stefan; Braun, Volkmar

    2008-01-01

    Among the 67 predicted TonB-dependent outer membrane transporters of Caulobacter crescentus, NagA was found to be essential for growth on N-acetyl-β-d-glucosamine (GlcNAc) and larger chitin oligosaccharides. NagA (93 kDa) has a predicted typical domain structure of an outer membrane transport protein: a signal sequence, the TonB box EQVVIT, a hatch domain of 147 residues, and a β-barrel composed of 22 antiparallel β-strands linked by large surface loops and very short periplasmic turns. Mutations in tonB1 and exbBD, known to be required for maltose transport via MalA in C. crescentus, and in two additional predicted tonB genes (open reading frames cc2327 and cc3508) did not affect NagA-mediated GlcNAc uptake. nagA is located in a gene cluster that encodes a predicted PTS sugar transport system and two enzymes that convert GlcNAc-6-P to fructose-6-P. Since a nagA insertion mutant did not grow on and transport GlcNAc, diffusion of GlcNAc through unspecific porins in the outer membrane is excluded. Uptake of GlcNAc into tonB and exbBD mutants and reduction but not abolishment of GlcNAc transport by agents which dissipate the electrochemical potential of the cytoplasmic membrane (0.1 mM carbonyl cyanide 3-chlorophenylhydrazone and 1 mM 2,4-dinitrophenol) suggest diffusion of GlcNAc through a permanently open pore of NagA. Growth on (GlcNAc)3 and (GlcNAc)5 requires ExbB and ExbD, indicating energy-coupled transport by NagA. We propose that NagA forms a small pore through which GlcNAc specifically diffuses into the periplasm and functions as an energy-coupled transporter for the larger chitin oligosaccharides. PMID:18539735

  5. NagA-dependent uptake of N-acetyl-glucosamine and N-acetyl-chitin oligosaccharides across the outer membrane of Caulobacter crescentus.

    PubMed

    Eisenbeis, Simone; Lohmiller, Stefanie; Valdebenito, Marianne; Leicht, Stefan; Braun, Volkmar

    2008-08-01

    Among the 67 predicted TonB-dependent outer membrane transporters of Caulobacter crescentus, NagA was found to be essential for growth on N-acetyl-beta-D-glucosamine (GlcNAc) and larger chitin oligosaccharides. NagA (93 kDa) has a predicted typical domain structure of an outer membrane transport protein: a signal sequence, the TonB box EQVVIT, a hatch domain of 147 residues, and a beta-barrel composed of 22 antiparallel beta-strands linked by large surface loops and very short periplasmic turns. Mutations in tonB1 and exbBD, known to be required for maltose transport via MalA in C. crescentus, and in two additional predicted tonB genes (open reading frames cc2327 and cc3508) did not affect NagA-mediated GlcNAc uptake. nagA is located in a gene cluster that encodes a predicted PTS sugar transport system and two enzymes that convert GlcNAc-6-P to fructose-6-P. Since a nagA insertion mutant did not grow on and transport GlcNAc, diffusion of GlcNAc through unspecific porins in the outer membrane is excluded. Uptake of GlcNAc into tonB and exbBD mutants and reduction but not abolishment of GlcNAc transport by agents which dissipate the electrochemical potential of the cytoplasmic membrane (0.1 mM carbonyl cyanide 3-chlorophenylhydrazone and 1 mM 2,4-dinitrophenol) suggest diffusion of GlcNAc through a permanently open pore of NagA. Growth on (GlcNAc)(3) and (GlcNAc)(5) requires ExbB and ExbD, indicating energy-coupled transport by NagA. We propose that NagA forms a small pore through which GlcNAc specifically diffuses into the periplasm and functions as an energy-coupled transporter for the larger chitin oligosaccharides. PMID:18539735

  6. N-acetyl-cysteine attenuates neuropathic pain by suppressing matrix metalloproteinases.

    PubMed

    Li, Jiajie; Xu, Lujie; Deng, Xueting; Jiang, Chunyi; Pan, Cailong; Chen, Lu; Han, Yuan; Dai, Wenling; Hu, Liang; Zhang, Guangqin; Cheng, Zhixiang; Liu, Wentao

    2016-08-01

    The treatment of neuropathic pain remains a clinical challenge because of its unclear mechanisms and broad clinical morbidity. Matrix metalloproteinase (MMP)-9 and MMP-2 have previously been described as key components in neuropathic pain because of their facilitation of inflammatory cytokine maturation and induction of neural inflammation. Therefore, the inhibition of MMPs may represent a novel therapeutic approach to the treatment of neuropathic pain. In this study, we report that N-acetyl-cysteine (NAC), which is a broadly used respiratory drug, significantly attenuates neuropathic pain through a unique mechanism of MMP inhibition. Both the in vitro (0.1 mM) and in vivo application of NAC significantly suppressed the activity of MMP-9/2. Orally administered NAC (50, 100, and 200 mg/kg) not only postponed the occurrence but also inhibited the maintenance of chronic constrictive injury (CCI)-induced neuropathic pain in rats. The administration of NAC blocked the maturation of interleukin-1β, which is a critical substrate of MMPs, and markedly suppressed the neuronal activation induced by CCI, including inhibiting the phosphorylation of protein kinase Cγ, NMDAR1, and mitogen-activated protein kinases. Finally, NAC significantly inhibited CCI-induced microglia activation but elicited no notable effects on astrocytes. These results demonstrate an effective and safe approach that has been used clinically to alleviate neuropathic pain through the powerful inhibition of the activation of MMPs. PMID:27075430

  7. N-acetyl-L-histidine, a Prominent Biomolecule in Brain and Eye of Poikilothermic Vertebrates.

    PubMed

    Baslow, Morris H; Guilfoyle, David N

    2015-01-01

    N-acetyl-L-histidine (NAH) is a prominent biomolecule in brain, retina and lens of poikilothermic vertebrates. In fish lens, NAH exhibits an unusual compartmentalized metabolism. It is synthesized from L-histidine (His) and acetyl Co-enzyme A. However, NAH cannot be catabolized by lens cells. For its hydrolysis, NAH is exported to ocular fluid where a specific acylase cleaves His which is then actively taken up by lens and re-synthesized into NAH. This energy-dependent cycling suggested a pump mechanism operating at the lens/ocular fluid interface. Additional studies led to the hypothesis that NAH functioned as a molecular water pump (MWP) to maintain a highly dehydrated lens and avoid cataract formation. In this process, each NAH molecule released to ocular fluid down its gradient carries with it 33 molecules of bound water, effectively transporting the water against a water gradient. In ocular fluid the bound water is released for removal from the eye by the action of NAH acylase. In this paper, we demonstrate for the first time the identification of NAH in fish brain using proton magnetic resonance spectroscopy (MRS) and describe recent evidence supporting the NAH MWP hypothesis. Using MRS, we also document a phylogenetic transition in brain metabolism between poikilothermic and homeothermic vertebrates. PMID:25919898

  8. N-acetyl-l-histidine, a Prominent Biomolecule in Brain and Eye of Poikilothermic Vertebrates

    PubMed Central

    Baslow, Morris H.; Guilfoyle, David N.

    2015-01-01

    N-acetyl-l-histidine (NAH) is a prominent biomolecule in brain, retina and lens of poikilothermic vertebrates. In fish lens, NAH exhibits an unusual compartmentalized metabolism. It is synthesized from l-histidine (His) and acetyl Co-enzyme A. However, NAH cannot be catabolized by lens cells. For its hydrolysis, NAH is exported to ocular fluid where a specific acylase cleaves His which is then actively taken up by lens and re-synthesized into NAH. This energy-dependent cycling suggested a pump mechanism operating at the lens/ocular fluid interface. Additional studies led to the hypothesis that NAH functioned as a molecular water pump (MWP) to maintain a highly dehydrated lens and avoid cataract formation. In this process, each NAH molecule released to ocular fluid down its gradient carries with it 33 molecules of bound water, effectively transporting the water against a water gradient. In ocular fluid the bound water is released for removal from the eye by the action of NAH acylase. In this paper, we demonstrate for the first time the identification of NAH in fish brain using proton magnetic resonance spectroscopy (MRS) and describe recent evidence supporting the NAH MWP hypothesis. Using MRS, we also document a phylogenetic transition in brain metabolism between poikilothermic and homeothermic vertebrates. PMID:25919898

  9. N-Acetyl Cysteine in the Treatment of Obsessive Compulsive and Related Disorders: A Systematic Review

    PubMed Central

    Oliver, Georgina; Dean, Olivia; Camfield, David; Blair-West, Scott; Ng, Chee; Berk, Michael; Sarris, Jerome

    2015-01-01

    Objective Obsessive compulsive and related disorders are a collection of debilitating psychiatric disorders in which the role of glutamate dysfunction in the underpinning neurobiology is becoming well established. N-acetyl cysteine (NAC) is a glutamate modulator with promising therapeutic effect. This paper presents a systematic review of clinical trials and case reports exploring the use of NAC for these disorders. A further objective was to detail the methodology of current clinical trials being conducted in the area. Methods PubMed, Web of Science and Cochrane Library Database were searched for human clinical trials or case reports investigating NAC in the treatment of obsessive compulsive disorder (OCD) or obsessive compulsive related disorders. Researchers with known involvement in NAC studies were contacted for any unpublished data. Results Four clinical trials and five case reports/series were identified. Study durations were commonly 12-weeks, using 2,400–3,000 mg/day of NAC. Overall, NAC demonstrates activity in reducing the severity of symptoms, with a good tolerability profile and minimal adverse effects. Currently there are three ongoing randomized controlled trials using NAC for OCD (two adults and one pediatric), and one for excoriation. Conclusion Encouraging results have been demonstrated from the few pilot studies that have been conducted. These results are detailed, in addition to a discussion of future potential research. PMID:25912534

  10. The effect of N-acetyl-L-cysteine on the viscosity of ileal neobladder mucus.

    PubMed

    Schrier, B P; Lichtendonk, W J; Witjes, J A

    2002-05-01

    N-acetyl-L-cysteine (NAC) proved to be an effective mucolytic in pulmonary secretions. Our goal was to investigate the in vitro effect of NAC on viscosity of ileal neobladder mucus. The urine of a patient with an ileal neobladder was collected during the first 7 days postoperatively and stored in a refrigerator. After precipitation, the urine was decanted. The residue was stirred to a homogeneous suspension. To samples of 4.5 ml mucus, 0.5 ml NAC 10% was added. To the control sample, 0.5 ml water was added. The samples were incubated in a water bath at 37 degrees C for 5, 30 and 60 min. Viscosity was measured in the Bohlin VOR Rheometer. The viscosity of the ileal neobladder mucus decreased quickly after incubating with NAC 10%. Viscosity increased slightly after I h of incubation. The viscosity in the control sample was higher than in the other incubated samples. NAC was found to decrease the viscosity of ileal neobladder mucus, supporting the in vivo experience that NAC can be useful in patients with an ileal neobladder to facilitate the evacuation of mucus by decreasing viscosity. PMID:12088194

  11. N-acetyl -β-D-glucosaminidase activity in cow milk as an indicator of mastitis.

    PubMed

    Hovinen, Mari; Simojoki, Heli; Pösö, Reeta; Suolaniemi, Jenni; Kalmus, Piret; Suojala, Leena; Pyörälä, Satu

    2016-05-01

    Activity of lysosomal N-acetyl-β-d-glucosaminidase (NAGase) in milk has been used as an indicator of bovine mastitis. We studied NAGase activity of 808 milk samples from healthy quarters and quarters of cows with spontaneous subclinical and clinical mastitis. Associations between milk NAGase activity and milk somatic cell count (SCC), mastitis causing pathogen, quarter, parity, days in milk (DIM) and season were studied. In addition, the performance of NAGase activity in detecting clinical and subclinical mastitis and distinguishing infections caused by minor and major bacteria was investigated. Our results indicate that NAGase activity can be used to detect both subclinical and clinical mastitis with a high level of accuracy (0·85 and 0·99). Incomplete correlation between NAGase activity and SCC suggests that a substantial proportion of NAGase activity comes from damaged epithelial cells of the udder in addition to somatic cells. We therefore recommend determination of NAGase activity from quarter foremilk after at least six hours from the last milking using the method described. Samples should be frozen before analysis. NAGase activity should be interpreted according to DIM, at least during the first month of lactation. Based on the results of the present study, a reference value for normal milk NAGase activity of 0·1-1·04 pmoles 4-MU/min/μl for cows with ≥30 DIM (196 samples) could be proposed. We consider milk NAGase activity to be an accurate indicator of subclinical and clinical mastitis. PMID:27210494

  12. Synthesis, characterization, antibacterial activity and quantum chemical studies of N'-Acetyl propane sulfonic acid hydrazide

    NASA Astrophysics Data System (ADS)

    Alyar, Saliha; Alyar, Hamit; Ozdemir, Ummuhan Ozmen; Sahin, Omer; Kaya, Kerem; Ozbek, Neslihan; Gunduzalp, Ayla Balaban

    2015-08-01

    A new N'-Acetyl propane sulfonic acid hydrazide, C3H7sbnd SO2sbnd NHsbnd NHsbnd COCH3 (Apsh, an sulfon amide compound) has been synthesized for the first time. The structure of Apsh was investigated using elemental analysis, spectral (IR, 1H/13C NMR) measurements. In addition, molecular structure of the Apsh was determined by single crystal X-ray diffraction technique and found that the compound crystallizes in monoclinic, space group P 21/c. 1H and 13C shielding tensors for crystal structure were calculated with GIAO/DFT/B3LYP/6-311++G(d,p) methods in CDCl3. The structure of Apsh is optimized using Density Functional Theory (DFT) method. The vibrational band assignments were performed at B3LYP/6-311++G(d,p) theory level combined with scaled quantum mechanics force field (SQMFF) methodology. The theoretical IR frequencies are found to be in good agreement with the experimental IR frequencies. Nonlinear optical (NLO) behaviour of Apsh is also examined by the theoretically predicted values of dipole moment (μ), polarizability (α0) and first hyperpolarizability (βtot). The antibacterial activities of synthesized compound were studied against Gram positive bacteria: Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 23212, Staphylococcus epidermidis ATCC 34384, Gram negative bacteria: Eschericha coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumoniae ATCC 70063 by using microdilution method (as MICs) and disc diffusion method.

  13. A nanoparticle delivery vehicle for S-nitroso-N-acetyl cysteine: Sustained vascular response

    PubMed Central

    Nacharaju, Parimala; Tuckman-Vernon, Chaim; Maier, Keith E.; Chouake, Jason; Friedman, Adam; Cabrales, Pedro; Friedman, Joel M.

    2014-01-01

    Interest in the development of nitric oxide (NO) based therapeutics has grown exponentially owing to its well elucidated and established biological functions. In line with this surge, S-nitroso thiol (RSNO) therapeutics are also receiving more attention in recent years both as potential stable sources of NO as well as for their ability to serve as S-nitrosating agents; S-nitrosation of protein thiols is implicated in many physiological processes. We describe two hydrogel based RSNO containing nanoparticle platforms. In one platform the SNO groups are covalently attached to the particles (SNO-np) and the other contains S-nitroso-N-acetyl cysteine encapsulated within the particles (NAC-SNO-np). Both platforms function as vehicles for sustained activity as trans-S-nitrosating agents. NAC-SNO-np exhibited higher efficiency for generating GSNO from GSH and maintained higher levels of GSNO concentration for longer time (24 h) as compared to SNO-np as well as a previously characterized nitric oxide releasing platform, NO-np (nitric oxide releasing nanoparticles). In vivo, intravenous infusion of the NAC-SNO-np and NO-np resulted in sustained decreases in mean arterial pressure, though NAC-SNO-np induced longer vasodilatory effects as compared to the NO-np. Serum chemistries following infusion demonstrated no toxicity in both treatment groups. Together, these data suggest that the NAC-SNO-np represents a novel means to both study the biologic effects of nitrosothiols and effectively capitalize on its therapeutic potential. PMID:22705913

  14. The Role of Poly N Acetyl Glucosamine Nanofibers in Cutaneous Wound Healing

    NASA Astrophysics Data System (ADS)

    Buff-Lindner, Amanda Haley

    Treatment of cutaneous wounds with poly-N-acetyl-glucosamine nanofibers (pGlcNAc), a novel polysaccharide material derived from a marine diatom, results in increases in wound closure, antibacterial activities and innate immune responses. Treatment with nanofibers results in increased defensin, small antimicrobial peptides, expression both in vitro and in vivo. Induction of defensin expression results in bacterial clearance in a cutaneous wound model. Our data show that Akt1 plays a central role in the regulation of these activities. Interestingly, pGlcNAc treatment of cutaneous wounds in mice results in decreased scar sizes. Additionally, treatment of cutaneous wounds with pGlcNAc results in increased elasticity and a rescue of tensile strength. Masson Trichrome staining suggests that pGlcNAc treated wounds exhibit decreased collagen content as well as increased collagen alignment with collagen fibers oriented similarly to unwounded tissue. Utilizing a fibrin gel assay to analyze the effect of pGlcNAc nanofiber treatment on fibroblast alignment in vitro, pGlcNAc stimulation of embedded fibroblasts results in fibroblasts alignment as compared to untreated controls, by a process that is Akt1 dependent. Our data show that in Akt1 null animals pGlcNAc treatment does not increase tensile strength or elasticity. Taken together, our findings suggest that pGlcNAc nanofibers stimulate an Akt1 dependent pathway that results in wound closure, the proper alignment of fibroblasts, decreased scarring, and increased tensile strength during cutaneous wound healing.

  15. Polymeric N-acetyl-D-glucosamine (chitin) induces histionic activation in dogs.

    PubMed

    Okamoto, Y; Minami, S; Matsuhashi, A; Sashiwa, H; Saimoto, H; Shigemasa, Y; Tanigawa, T; Tanaka, Y; Tokura, S

    1993-10-01

    Analyses on the effects of polymeric N-acetyl-D-glucosamine (chitin), which was obtained from squid pen, on histiogenic activation in dogs were carried out with subcutaneous implants (5 x 5 cm2) of polyester non-woven fabric (NWF) supplemented with chitin (chitin group) and NWF (control group). These materials were implanted at 4 sites, on the lumbodorsal and lumbosacral subcutaneous tissues on both sides of the midline in each dog under general anesthesia. The implants and their surrounding tissues were isolated on post-implantation days (PIDs) 2, 4, 8, and 18 under general anesthesia. In the chitin group, the implant was organized gradually and its organization was completed on PID 18, when obvious angiogenesis toward the NWF was observed. On the other hand, in the control group, obvious angiogenesis toward the NWF was not observed macroscopically. Numbers of mononuclear (MN) and polymorphonuclear (PMN) cells concentrated around the implants on PID 2 were larger in the chitin than control group. In the chitin group, formation of granulating tissue around the implant was indicated on PID 4, whereas such a phenomenon was not observed in the control group. From these results, chitin accelerates the migration of MN and PMN cells to the NWF site with rapid follow-up organization of the NWF accompanied by angiogenesis. PMID:7506939

  16. Synthesis and characterization of a novel chitosan-N-acetyl-homocysteine thiolactone polymer using MES buffer.

    PubMed

    Ferris, C; Casas, M; Lucero, M J; de Paz, M V; Jiménez-Castellanos, M R

    2014-10-13

    We report a new "green" approach to synthesize a novel thiolated chitosan conjugate, chitosan-N-acetyl-homocysteine thiolactone (chitosan-AcHcys) using a "Good's buffers", 2-(N-morpholino)ethanesulfonic acid (MES). After that, the crosslinked Xr-chitosan-AcHcys was obtained only in the presence of air, without other reactants. The chitosan-AcHcys spectrum shows a partial incorporation of the thiolactone onto the polymer backbone. The derivative thermogravimetric analysis confirmed that chitosan-AcHcys is slightly less stable than starting chitosan; however, the peak profile is broadened which is indicative of deeper changes in the thermal degradation process. Also, aqueous dispersions with different concentrations of the crosslinked material (Xr-chitosan-AcHcys) were prepared and rheologically characterized. All aqueous dispersions are viscoelastic fluid with shear-thinning behavior. The viscosity of the dispersions (1-7% of chitosan-AcHcys) increases as a function of polymer concentration. So, we have achieved to disperse a high concentration of thiolated-chitosan derivative in water with different rheological characteristics, which could affect the drug release. PMID:25037337

  17. Two novel regulators of N-acetyl-galactosamine utilization pathway and distinct roles in bacterial infections.

    PubMed

    Zhang, Huimin; Ravcheev, Dmitry A; Hu, Dan; Zhang, Fengyu; Gong, Xiufang; Hao, Lina; Cao, Min; Rodionov, Dmitry A; Wang, Changjun; Feng, Youjun

    2015-12-01

    Bacterial pathogens can exploit metabolic pathways to facilitate their successful infection cycles, but little is known about roles of d-galactosamine (GalN)/N-acetyl-d-galactosamine (GalNAc) catabolism pathway in bacterial pathogenesis. Here, we report the genomic reconstruction of GalN/GalNAc utilization pathway in Streptococci and the diversified aga regulons. We delineated two new paralogous AgaR regulators for the GalN/GalNAc catabolism pathway. The electrophoretic mobility shift assays experiment demonstrated that AgaR2 (AgaR1) binds the predicted palindromes, and the combined in vivo data from reverse transcription quantitative polymerase chain reaction and RNA-seq suggested that AgaR2 (not AgaR1) can effectively repress the transcription of the target genes. Removal of agaR2 (not agaR1) from Streptococcus suis 05ZYH33 augments significantly the abilities of both adherence to Hep-2 cells and anti-phagocytosis against RAW264.7 macrophage. As anticipated, the dysfunction in AgaR2-mediated regulation of S. suis impairs its pathogenicity in experimental models of both mice and piglets. Our finding discovered two novel regulators specific for GalN/GalNAc catabolism and assigned them distinct roles into bacterial infections. To the best of our knowledge, it might represent a first paradigm that links the GalN/GalNAc catabolism pathway to bacterial pathogenesis. PMID:26540018

  18. Chitosan films with improved tensile strength and toughness from N-acetyl-cysteine mediated disulfide bonds.

    PubMed

    Miles, Kevin Barrett; Ball, Rebecca Lee; Matthew, Howard William Trevor

    2016-03-30

    To improve the mechanical properties of chitosan (Ct) materials without the use of cytotoxic crosslinkers, disulfide cross-linkable Ct was synthesized by grafting N-acetyl-cysteine (NAC) to Ct using carbodiimide chemistry. Cast films of NAC-Ct conjugates were prepared with degrees of substitution (DS) of 0%, 6%, 15%, and 20%, and the disulfide bond formation was induced by increasing the reaction media pH to 11. The tensile strength, breaking strain, elastic moduli and toughness of disulfide cross-linked polymers were analyzed by monotonic tensile testing of hydrated NAC-Ct films. Crystallinity was determined via XRD. Results demonstrated that NAC incorporation and crosslinking in chitosan produced tougher polymer films with 4-fold higher tensile strength (10 MPa) and 6-fold greater elongation (365%), but reduced crystallinity, compared to unmodified chitosan. The resilience of NAC-Ct films was evaluated by cyclic testing, and results demonstrate that increasing NAC content produced a more resilient material that dissipated less energy when deformed. These improved mechanical properties broaden chitosan's applicability towards the construction of mechanically robust implantable scaffolds for tissue regeneration. PMID:26794940

  19. An Additive Effect of Oral N-Acetyl Cysteine on Eradication of Helicobacter pylori

    PubMed Central

    Hamidian, Seyed Mohammad-Taghi; Aletaha, Najmeh-sadat; Taslimi, Reza; Montazeri, Mohammad

    2015-01-01

    Background. Helicobacter pylori is highly adapted to the gastric environment where it lives within or beneath the gastric mucous layer. The aim of this study was to evaluate whether the addition of N-acetyl cysteine to the treatment regimen of H. pylori infection would affect eradication rates of the disease. Methods. A total of 79 H. pylori positive patients were randomized to two therapeutic groups. Both groups received a 14-day course of three-drug regimen including amoxicillin/clarithromycin/omeprazole. Experimental group (38 subjects) received NAC, and control group (41 subjects) received placebo, besides three-drug regimen. H. pylori eradication was evaluated by urea breath test at least 4 weeks after the cessation of therapy. Results. The rate of H. pylori eradication was 72.9% and 60.9% in experimental and control groups, respectively (P = 0.005). By logistic regression modeling, female gender (OR 3.68, 95% CI: 1.06–5.79; P = 0.040) and treatment including NAC (OR 1.88, 95% CI: 0.68–3.15; P = 0.021) were independent factors associated with H. pylori eradication. Conclusion. The results of the present study show that NAC has an additive effect on the eradication rates of H. pylori obtained with three-drug regimen and appears to be a promising means of eradicating H. pylori infection. PMID:26421191

  20. Neonatal administration of N-acetyl-L-aspartyl-L-glutamate induces early neurodegeneration in hippocampus and alters behaviour in young adult rats.

    PubMed

    Bubeníková-Valesová, Vera; Balcar, Vladimir J; Tejkalová, Hana; Langmeier, Milos; St'astný, Frantisek

    2006-01-01

    N-acetyl-L-aspartyl-L-glutamate (NAAG) is a dipeptide that could be considered a sequestered form of L-glutamate. As much as 25% of L-glutamate in brain may be present in the form of NAAG. NAAG is also one of the most abundant neuroactive small molecules in the CNS: it is an agonist at Group II metabotropic glutamate receptors (mGluR II) and, at higher concentrations, at the N-methyl-D-aspartate (NMDA) type of ionotropic glutamate receptors. As such, NAAG can be either neuroprotective or neurotoxic and, in fact, both characteristics have been discussed and described in the literature. In the present studies, 250 nmol NAAG was infused into each lateral cerebral ventricle of 12-day-old rat pups and, using Nissl-stained sections, neurodegeneration in the hippocampus was evaluated 24 or 96 h after the infusion. In several experiments, the neuronal death was also visualised by Fluoro-Jade B staining and studied by TUNEL technique. Some of the NAAG-treated animals were allowed to survive until 50 days post partum and subjected to behavioural (open field) tests. The administration of NAAG to 12-day-old rats resulted in extensive death of neurons particularly in the dentate gyrus of the hippocampus. The neurodegeneration was, in part, prevented by administration of an NMDA receptor antagonist MK-801 (0.1 mg/kg). The nuclear DNA-fragmentation demonstrated by TUNEL technique pointed to the presence of non-specific single-strand DNA cleavage. The NAAG-associated neonatal neuronal damage may have perturbed development of synaptic circuitry during adolescence as indicated by an altered performance of the experimental animals in the open field testing (changes in grooming activity) at postnatal day 50. The results underscore the potential neurotoxicity of NAAG in neonatal rat brain and implicate neonatally induced, NMDA receptor-mediated neuronal loss in the development of abnormal behaviour in young adult rats. PMID:16540202

  1. Glutamate excitotoxicity in neurons triggers mitochondrial and endoplasmic reticulum accumulation of Parkin, and, in the presence of N-acetyl cysteine, mitophagy

    PubMed Central

    Van Laar, Victor S.; Roy, Nikita; Liu, Annie; Rajprohat, Swati; Arnold, Beth; Dukes, April A.; Holbein, Cory D.; Berman, Sarah B.

    2014-01-01

    Disruption of the dynamic properties of mitochondria (fission, fusion, transport, degradation, and biogenesis) has been implicated in the pathogenesis of neurodegenerative disorders, including Parkinson’s disease (PD). Parkin, the product of gene PARK2 whose mutation causes familial PD, has been linked to mitochondrial quality control via its role in regulating mitochondrial dynamics, including mitochondrial degradation via mitophagy. Models using mitochondrial stressors in numerous cell types have elucidated a PINK1-dependent pathway whereby Parkin accumulates on damaged mitochondria and targets them for mitophagy. However, the role Parkin plays in regulating mitochondrial homeostasis specifically in neurons has been less clear. We examined whether a stressor linked to neurodegeneration, glutamate excitotoxicity, elicits Parkin-mitochondrial translocation and mitophagy in neurons. We found that brief, acute exposure to glutamate causes Parkin translocation to mitochondria in neurons, in a calcium- and N-methyl-D-aspartate (NMDA) receptor-dependent manner. In addition, we found that Parkin accumulates on endoplasmic reticulum (ER) and mitochondrial/ER junctions following excitotoxicity, supporting a role for Parkin in mitochondrial-ER crosstalk in mitochondrial homeostasis. Despite significant Parkin-mitochondria translocation, however, we did not observe mitophagy under these conditions. To further investigate, we examined the role of glutamate-induced oxidative stress in Parkin-mitochondria accumulation. Unexpectedly, we found that glutamate-induced accumulation of Parkin on mitochondria was promoted by the antioxidant N-acetyl cysteine (NAC), and that co-treatment with NAC facilitated Parkin-associated mitophagy. These results suggest the possibility that mitochondrial depolarization and oxidative damage may have distinct pathways associated with Parkin function in neurons, which may be critical in understanding the role of Parkin in neurodegeneration. PMID

  2. Lactose-egg yolk diluent supplemented with N-acetyl-D-glucosamine affect acrosome morphology and motility of frozen-thawed boar sperm.

    PubMed

    Yi, Y J; Im, G S; Park, C S

    2002-12-16

    These experiments were carried out to investigate the effect of N-acetyl-D-glucosamine, and to obtain additional information about the effect of orvus es paste (OEP) and egg yolk concentration in the freezing of boar sperm in the maxi-straw. The highest post-thaw acrosomes of normal apical ridge (NAR) and motility were obtained with 0.025 or 0.05% N-acetyl-D-glucosamine concentration in the first diluent. However, there were no effects of N-acetyl-D-glucosamine among the diluents with or without N-acetyl-D-glucosamine at the second dilution. The N-acetyl-D-glucosamine in the first and second diluents was added at room temperatures (20-23 degrees C) and 5 degrees C, respectively. It is suggested that the temperature of N-acetyl-D-glucosamine addition is important for the effect of boar sperm protection during freezing and thawing. When the 0.05% N-acetyl-D-glucosamine was supplemented in the first diluent, the optimum final OEP content was 0.5%. The optimum content of egg yolk in the diluent with 0.05% N-acetyl-D-glucosamine concentration was 20% and egg yolk was one of the main cryoprotective agents. In conclusion, we found out that the diluent with 0.025 or 0.05% soluble N-acetyl-D-glucosamine in the first diluent, 0.5% final orvus es paste concentration and 20% egg yolk concentration significantly enhanced NAR acrosomes and motility of boar sperm after freezing and thawing. PMID:12417120

  3. Development of Unsymmetrical Dyads As Potent Noncarbohydrate-Based Inhibitors against Human β-N-Acetyl-d-hexosaminidase.

    PubMed

    Guo, Peng; Chen, Qi; Liu, Tian; Xu, Lin; Yang, Qing; Qian, Xuhong

    2013-06-13

    Human β-N-acetyl-d-hexosaminidase has gained much attention due to its roles in several pathological processes and been considered as potential targets for disease therapy. A novel and efficient skeleton, which was an unsymmetrical dyad containing naphthalimide and methoxyphenyl moieties with an alkylamine spacer linkage as a noncarbohydrate-based inhibitor, was synthesized, and the activities were valuated against human β-N-acetyl-d-hexosaminidase. The most potent inhibitor exhibits high inhibitory activity with K i values of 0.63 μM. The straightforward synthetic manners of these unsymmetrical dyads and understanding of the binding model could be advantageous for further structure optimization and development of new therapeutic agents for Hex-related diseases. PMID:24900704

  4. Development of Unsymmetrical Dyads As Potent Noncarbohydrate-Based Inhibitors against Human β-N-Acetyl-d-hexosaminidase

    PubMed Central

    2013-01-01

    Human β-N-acetyl-d-hexosaminidase has gained much attention due to its roles in several pathological processes and been considered as potential targets for disease therapy. A novel and efficient skeleton, which was an unsymmetrical dyad containing naphthalimide and methoxyphenyl moieties with an alkylamine spacer linkage as a noncarbohydrate-based inhibitor, was synthesized, and the activities were valuated against human β-N-acetyl-d-hexosaminidase. The most potent inhibitor exhibits high inhibitory activity with Ki values of 0.63 μM. The straightforward synthetic manners of these unsymmetrical dyads and understanding of the binding model could be advantageous for further structure optimization and development of new therapeutic agents for Hex-related diseases. PMID:24900704

  5. Exploration of the full conformational space of N-acetyl-L-glutamate-N-methylamide . An ab initio and DFT study

    NASA Astrophysics Data System (ADS)

    Masman, M. F.; Zamora, M. A.; Rodríguez, A. M.; Fidanza, N. G.; Peruchena, N. M.; Enriz, R. D.; Csizmadia, I. G.

    2002-09-01

    A conformational and electronic study on N-acetyl-L-glutamate-N-methylamide was carried out. Theoretical computational analysis revealed 21 different conformations at the RB3LYP/6-31G(d) level of theory. Ab initio calculations at two levels of theory (RHF/3-21G and RHF/6-31G(d)) were also performed. All side-chain conformations were explored for this compound. N-acetyl-L-glutamate-N-methylamide displayed a different conformational behaviour in comparison with other amino acids possessing shorter side-chains. These results can be attributed, at least in part, to the side-chain-backbone interactions, which are stabilizing the low-energy conformations in this molecule.

  6. Design, synthesis, and biological activity of a potent inhibitor of the neuropeptidase N-acetylated alpha-linked acidic dipeptidase.

    PubMed

    Jackson, P F; Cole, D C; Slusher, B S; Stetz, S L; Ross, L E; Donzanti, B A; Trainor, D A

    1996-01-19

    A series of substituted phosphonate derivatives were designed and synthesized in order to study the ability of these compounds to inhibit the neuropeptidase N-acetylated alpha-linked acidic dipeptidase (NAALADase). The molecules were shown to act as inhibitors of the enzyme, with the most potent (compound 3) having a Ki of 0.275 nM. The potency of this compound is more than 1000 times greater than that of previously reported inhibitors of the enzyme. NAALADase is responsible for the catabolism of the abundant neuropeptide N-acetyl-aspartylglutamate (NAAG) into N-acetylaspartate and glutamate. NAAG has been proposed to be a neurotransmitter at a subpopulation of glutamate receptors; alternatively, NAAG has been suggested to act as a storage form of synaptic glutamate. As a result, inhibition of NAALADase may show utility as a therapeutic intervention in diseases in which altered levels of glutamate are thought to be involved. PMID:8558536

  7. Maize Root Lectins Mediate the Interaction with Herbaspirillum seropedicae via N-Acetyl Glucosamine Residues of Lipopolysaccharides

    PubMed Central

    Balsanelli, Eduardo; Tuleski, Thalita Regina; de Baura, Valter Antonio; Yates, Marshall Geoffrey; Chubatsu, Leda Satie; de Oliveira Pedrosa, Fabio; de Souza, Emanuel Maltempi; Monteiro, Rose Adele

    2013-01-01

    Herbaspirillum seropedicae is a plant growth-promoting diazotrophic betaproteobacterium which associates with important crops, such as maize, wheat, rice and sugar-cane. We have previously reported that intact lipopolysaccharide (LPS) is required for H. seropedicae attachment and endophytic colonization of maize roots. In this study, we present evidence that the LPS biosynthesis gene waaL (codes for the O-antigen ligase) is induced during rhizosphere colonization by H. seropedicae. Furthermore a waaL mutant strain lacking the O-antigen portion of the LPS is severely impaired in colonization. Since N-acetyl glucosamine inhibits H. seropedicae attachment to maize roots, lectin-like proteins from maize roots (MRLs) were isolated and mass spectrometry (MS) analysis showed that MRL-1 and MRL-2 correspond to maize proteins with a jacalin-like lectin domain, while MRL-3 contains a B-chain lectin domain. These proteins showed agglutination activity against wild type H. seropedicae, but failed to agglutinate the waaL mutant strain. The agglutination reaction was severely diminished in the presence of N-acetyl glucosamine. Moreover addition of the MRL proteins as competitors in H. seropedicae attachment assays decreased 80-fold the adhesion of the wild type to maize roots. The results suggest that N-acetyl glucosamine residues of the LPS O-antigen bind to maize root lectins, an essential step for efficient bacterial attachment and colonization. PMID:24130823

  8. Structure and Reactivity of the N-Acetyl-Cysteine Radical Cation and Anion: Does Radical Migration Occur?

    NASA Astrophysics Data System (ADS)

    Osburn, Sandra; Berden, Giel; Oomens, Jos; O'Hair, Richard A. J.; Ryzhov, Victor

    2011-10-01

    The structure and reactivity of the N-acetyl-cysteine radical cation and anion were studied using ion-molecule reactions, infrared multi-photon dissociation (IRMPD) spectroscopy, and density functional theory (DFT) calculations. The radical cation was generated by first nitrosylating the thiol of N-acetyl-cysteine followed by the homolytic cleavage of the S-NO bond in the gas phase. IRMPD spectroscopy coupled with DFT calculations revealed that for the radical cation the radical migrates from its initial position on the sulfur atom to the α-carbon position, which is 2.5 kJ mol-1 lower in energy. The radical migration was confirmed by time-resolved ion-molecule reactions. These results are in contrast with our previous study on cysteine methyl ester radical cation (Osburn et al., Chem. Eur. J. 2011, 17, 873-879) and the study by Sinha et al. for cysteine radical cation ( Phys. Chem. Chem. Phys. 2010, 12, 9794-9800) where the radical was found to stay on the sulfur atom as formed. A similar approach allowed us to form a hydrogen-deficient radical anion of N-acetyl-cysteine, (M - 2H) •- . IRMPD studies and ion-molecule reactions performed on the radical anion showed that the radical remains on the sulfur, which is the initial and more stable (by 63.6 kJ mol-1) position, and does not rearrange.

  9. Distinct roles of N-acetyl and 5-methoxy groups in the antiproliferative and neuroprotective effects of melatonin.

    PubMed

    Letra-Vilela, Ricardo; Sánchez-Sánchez, Ana María; Rocha, Ana Maia; Martin, Vanesa; Branco-Santos, Joana; Puente-Moncada, Noelia; Santa-Marta, Mariana; Outeiro, Tiago Fleming; Antolín, Isaac; Rodriguez, Carmen; Herrera, Federico

    2016-10-15

    Melatonin (N-acetyl-5-methoxytryptamine) is a highly pleiotropic hormone with antioxidant, antiproliferative, oncolytic and neuroprotective properties. Here, we present evidence that the N-acetyl side chain plays a key role in melatonin's antiproliferative effect in HT22 and sw-1353 cells, but it does so at the expense of antioxidant and neuroprotective properties. Removal of the N-acetyl group enhances the antioxidant and neuroprotective properties of the indole, but it can lead to toxic methamphetamine-like effects in several cell lines. Inhibition of NFkB mimicked melatonin's antiproliferative and antioxidant effects, but not neuroprotection. Our results strongly suggest that neuroprotective and antiproliferative effects of melatonin rely on different parts of the molecule and are likely mediated by different mechanisms. We also predict that melatonin metabolism by target cells could determine whether melatonin inhibits cell proliferation, prevents toxicity or induces cell death (e.g. apoptosis or autophagy). These observations could have important implications for the rational use of melatonin in personalized medicine. PMID:27402602

  10. Hydration and N-acetyl-l-cysteine alter the microstructure of human nail and bovine hoof: implications for drug delivery.

    PubMed

    Nogueiras-Nieto, L; Gómez-Amoza, J L; Delgado-Charro, M B; Otero-Espinar, F J

    2011-12-20

    This work aimed to (a) characterize the microstructure and porosity of human nail and bovine hoof by mercury intrusion porosimetry and SEM image analysis, (b) study the effects of hydration and of N-acetyl-l-cysteine treatment on the microstructure of both membranes, and (c) determine whether the microstructural modifications were associated with changes in drug penetration measured by standard diffusion studies. Bovine hoof surface is more porous than nail surface although there were no differences between the mean surface pore sizes. Hydration and N-acetyl-l-cysteine increased the roughness and apparent surface porosity, and the porosity determined by mercury intrusion porosimetry of both membranes. Pore-Cor™ was used to generate tridimensional structures having percolation characteristics comparable to nail and hooves. The modeled structures were horizontally banded having an inner less-porous area which disappeared upon treatment. Treatment increased the predicted permeability of the simulated structures. Triamcinolone permeation increased significantly for hooves treated N-acetyl-l-cysteine, i.e., the membranes for which microstructural and permeability changes were the largest. Thus, microstructural changes determined via mercury intrusion porosimetry and subsequently modeled by Pore-Cor™ were related to drug diffusion. Further refinement of the technique will allow fast screening of penetration enhancers to be used in ungual drug delivery. PMID:21906642

  11. Maize root lectins mediate the interaction with Herbaspirillum seropedicae via N-acetyl glucosamine residues of lipopolysaccharides.

    PubMed

    Balsanelli, Eduardo; Tuleski, Thalita Regina; de Baura, Valter Antonio; Yates, Marshall Geoffrey; Chubatsu, Leda Satie; Pedrosa, Fabio de Oliveira; de Souza, Emanuel Maltempi; Monteiro, Rose Adele

    2013-01-01

    Herbaspirillum seropedicae is a plant growth-promoting diazotrophic betaproteobacterium which associates with important crops, such as maize, wheat, rice and sugar-cane. We have previously reported that intact lipopolysaccharide (LPS) is required for H. seropedicae attachment and endophytic colonization of maize roots. In this study, we present evidence that the LPS biosynthesis gene waaL (codes for the O-antigen ligase) is induced during rhizosphere colonization by H. seropedicae. Furthermore a waaL mutant strain lacking the O-antigen portion of the LPS is severely impaired in colonization. Since N-acetyl glucosamine inhibits H. seropedicae attachment to maize roots, lectin-like proteins from maize roots (MRLs) were isolated and mass spectrometry (MS) analysis showed that MRL-1 and MRL-2 correspond to maize proteins with a jacalin-like lectin domain, while MRL-3 contains a B-chain lectin domain. These proteins showed agglutination activity against wild type H. seropedicae, but failed to agglutinate the waaL mutant strain. The agglutination reaction was severely diminished in the presence of N-acetyl glucosamine. Moreover addition of the MRL proteins as competitors in H. seropedicae attachment assays decreased 80-fold the adhesion of the wild type to maize roots. The results suggest that N-acetyl glucosamine residues of the LPS O-antigen bind to maize root lectins, an essential step for efficient bacterial attachment and colonization. PMID:24130823

  12. Simple, rapid spectrophotometry of urinary N-acetyl-beta-D-glucosaminidase, with use of a new chromogenic substrate.

    PubMed

    Noto, A; Ogawa, Y; Mori, S; Yoshioka, M; Kitakaze, T; Hori, T; Nakamura, M; Miyake, T

    1983-10-01

    We have developed a new spectrophotometric assay for urinary N-acetyl-beta-D-glucosaminidase (NAGase) with use of sodio m-cresolsulfonphthaleinyl N-acetyl-beta-D-glucosaminide (MCP-NAG). MCP-NAG was synthesized from acetochloro-glucosamine and m-cresolsulfonphthalein (MCP) in four steps. MCP-NAG reacts well with NAGase (Km = 0.41 mmol/L) and is highly water soluble. The absorption maximum and molar absorptivity of the aglycone MCP are 580 nm and 40 670, respectively. Spectral overlap of interfering substances at 580 nm is almost negligible, so that the urine blank can be omitted from the assay procedure. The high molar absorptivity of MCP gives sufficient analytical sensitivity at a reaction time of 15 min. The correlation between the MCP-NAG method (y) and the fluorimetric method (x) involving 4-methylumbelliferyl N-acetyl-beta-D-glucosaminide is represented by the equation y = 0.995x - 0.669 (r = 0.991). Thus, the present method provides practical advantages over conventional methods, for use in the routine laboratory. PMID:6616814

  13. Distinct specificities of Mycobacterium tuberculosis and mammalian proteasomes for N-acetyl tripeptide substrates.

    PubMed

    Lin, Gang; Tsu, Christopher; Dick, Lawrence; Zhou, Xi K; Nathan, Carl

    2008-12-01

    The proteasome of Mycobacterium tuberculosis (Mtb) is a validated and drug-treatable target for therapeutics. To lay ground-work for developing peptide-based inhibitors with a useful degree of selectivity for the Mtb proteasome over those of the host, we used a library of 5,920 N-acetyl tripeptide-aminomethylcoumarins to contrast the substrate preferences of the recombinant Mtb proteasome wild type and open gate mutant, the Rhodococcus erythropolis proteasome, and the bovine proteasome with activator PA28. The Mtb proteasome was distinctive in strictly preferring P1 = tryptophan, particularly in combination with P3 = glycine, proline, lysine or arginine. Screening results were validated with Michalis-Menten kinetic analyses of 21 oligopeptide aminomethyl-coumarin substrates. Bortezomib, a proteasome inhibitor in clinical use, and 17 analogs varying only at P1 were used to examine the differential impact of inhibitors on human and Mtb proteasomes. The results with the inhibitor panel confirmed those with the substrate panel in demonstrating differential preferences of Mtb and mammalian proteasomes at the P1 amino acid. Changing P1 in bortezomib from Leu to m-CF(3)-Phe led to a 220-fold increase in IC(50) against the human proteasome, whereas changing a P1 Ala to m-F-Phe decreased the IC(50) 400-fold against the Mtb proteasome. The change of a P1 Ala to m-Cl-Phe led to an 8000-fold shift in inhibitory potency in favor of the Mtb proteasome, resulting in 8-fold selectivity. Combinations of preferred amino acids at different sites may thus improve the species selectivity of peptide-based inhibitors that target the Mtb proteasome. PMID:18829465

  14. [Comparison of urinary and seminal N-acetyl-beta-glucosaminidase isoenzymes].

    PubMed

    Yasumoto, R; Asakawa, M; Yamamoto, M; Doi, Y; Kawashima, H; Umeda, M; Tanabe, S; Nishisaka, N; Kakinoki, K; Maekawa, M

    1987-11-01

    N-acetyl-beta-glucosaminidase (NAG) and its isoenzymes were measured in the urine and seminal plasma of healthy volunteers. Urinary NAG level was 2.62 +/- 1.30 U/L (mean +/- standard deviation), 1.99 +/- 0.77 U/g creatinine and seminal NAG level was 2370 +/- 1007 U/l. Urinary NAG level was 2.59 +/- 1.44 U/l, 1.93 +/- 0.80 U/g creatinine in males and 2.67 +/- 1.15 U/l, 2.08 +/- 0.78 U/g creatinine in females, and there was no significant sex difference. NAG isoenzymes in the urine and seminal plasma were divided into two major peaks, A and B. The A:B ratio was 78.0 +/- 6.5: 21.9 +/- 6.5 in the urine and 24.7 +/- 3.2: 75.2 +/- 3.2 in the seminal plasma, and was significantly different. Urinary NAG isoenzyme was 80.3 +/- 6.7: 19.6 +/- 6.7 in males and 74.1 +/- 4.3: 25.9 +/- 4.3 in females, and there was no significant difference between the sexes. These results indicated that urinary and seminal NAG can be differentiated by measuring the isoenzymes. Furthermore, the comparison of seminal NAG isoenzymes before and after vasectomy indicated that seminal NAG may be affected not only by the sperm but also by the prostatic fluid. PMID:3445866

  15. N-Acetyl Cysteine (NAC)-Directed Detoxification of Methacryloxylethyl Cetyl Ammonium Chloride (DMAE-CB)

    PubMed Central

    Shan, Lequn; Wang, Yingjie; Tian, Min; Yang, Yanwei; Sun, Jinlong; Ban, Jinghao; Chen, Jihua

    2015-01-01

    Methacryloxylethyl cetyl ammonium chloride (DMAE-CB) is a polymerizable antibacterial monomer and has been proved as an effective strategy to achieve bioactive bonding with reliable bacterial inhibitory effects. However, the toxicity of DMAE-CB may hamper its wide application in clinical situations. Thus, this study was designed to investigate the toxicity of DMAE-CB and explore the possible protective effects of N-acetyl cysteine (NAC). High performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) analysis showed that chemical binding of NAC and DMAE-CB occurred in a time dependent manner. Pre-incubation of fourty-eight hours is required for adequate reaction between DMAE-CB and NAC. DMAE-CB reduced human dental pulp cells (hDPCs) viability in a dose-dependent manner. The toxic effects of DMAE-CB were accompanied by increased reactive oxygen species (ROS) level and reduced glutathione (GSH) content. NAC alleviated DMAE-CB-induced oxidative stress. Annexin V/ Propidium Iodide (PI) staining and Hoechst 33342 staining indicated that DMAE-CB induced apoptosis. Collapsed mitochondrial membrane potential (MMP) and activation of caspase-3 were also observed after DMAE-CB treatment. NAC rescued hDPCs from DMAE-CB-induced apoptosis, accompanied by lower level of MMP loss and caspase-3 activity. This study assists to elucidate the mechanism underlying the cytotoxic effects of DMAE-CB and provides theoretical supports for the searching of effective strategies to reduce toxicity of quaternary ammonium dental monomers. PMID:26274909

  16. A Preliminary Study: N-acetyl-L-cysteine Improves Semen Quality following Varicocelectomy

    PubMed Central

    Barekat, Foroogh; Tavalaee, Marziyeh; Deemeh, Mohammad Reza; Bahreinian, Mahsa; Azadi, Leila; Abbasi, Homayoun; Rozbahani, Shahla; Nasr-Esfahani, Mohammad Hossein

    2016-01-01

    Background Surgery is considered the primary treatment for male infertility from clinical varicocele. One of the main events associated with varicocele is excessive production of reactive oxygen species (ROS). N-acetyl-L-cysteine (NAC), an antioxidant that scavenges free radicals, is considered a supplement to alleviate glutathione (GSH) depletion during oxidative stress. Despite beneficial effects of NAC in other pathological events, there is no report on the effect of NAC in individuals with varicocele. Therefore, the aim of this study is to evaluate the outcome of NAC on semen quality, protamine content, DNA damage, oxidative stress and fertility following varicocelectomy. Materials and Methods This prospective clinical trial included 35 infertile men with varicocele randomly divided into control (n=20) and NAC (n=15) groups. We assessed semen parameters, protamine content [chromomycin A3 (CMA3)], DNA integrity [terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling (TUNEL)] and oxidative stress [2', 7'-dichlorodihydrofluorescein-diacetate (DCFH-DA)] before and three months after varicocelectomy. Results Percentage of abnormal semen parameters, protamine deficiency, DNA fragmentation and oxidative stress were significantly decreased in both groups compared to before surgery. We calculated the percentage of improvement in these parameters compared to before surgery for each group, then compared the results between the groups. Only percentage of protamine deficiency and DNA fragmentation significantly differed between the NAC and control groups. Conclusion The results of this study, for the first time, revealed that NAC improved chromatin integrity and pregnancy rate when administered as adjunct therapy post-varico- celectomy (Registeration Number: IRCT201508177223N5). PMID:27123209

  17. ROS inhibitor N-acetyl-L-cysteine antagonizes the activity of proteasome inhibitors.

    PubMed

    Halasi, Marianna; Wang, Ming; Chavan, Tanmay S; Gaponenko, Vadim; Hay, Nissim; Gartel, Andrei L

    2013-09-01

    NAC (N-acetyl-L-cysteine) is commonly used to identify and test ROS (reactive oxygen species) inducers, and to inhibit ROS. In the present study, we identified inhibition of proteasome inhibitors as a novel activity of NAC. Both NAC and catalase, another known scavenger of ROS, similarly inhibited ROS levels and apoptosis associated with H₂O₂. However, only NAC, and not catalase or another ROS scavenger Trolox, was able to prevent effects linked to proteasome inhibition, such as protein stabilization, apoptosis and accumulation of ubiquitin conjugates. These observations suggest that NAC has a dual activity as an inhibitor of ROS and proteasome inhibitors. Recently, NAC was used as a ROS inhibitor to functionally characterize a novel anticancer compound, piperlongumine, leading to its description as a ROS inducer. In contrast, our own experiments showed that this compound depicts features of proteasome inhibitors including suppression of FOXM1 (Forkhead box protein M1), stabilization of cellular proteins, induction of ROS-independent apoptosis and enhanced accumulation of ubiquitin conjugates. In addition, NAC, but not catalase or Trolox, interfered with the activity of piperlongumine, further supporting that piperlongumine is a proteasome inhibitor. Most importantly, we showed that NAC, but not other ROS scavengers, directly binds to proteasome inhibitors. To our knowledge, NAC is the first known compound that directly interacts with and antagonizes the activity of proteasome inhibitors. Taken together, the findings of the present study suggest that, as a result of the dual nature of NAC, data interpretation might not be straightforward when NAC is utilized as an antioxidant to demonstrate ROS involvement in drug-induced apoptosis. PMID:23772801

  18. Can N-acetyl-L-cysteine affect zinc metabolism when used as a paracetamol antidote?

    PubMed

    Brumas, V; Hacht, B; Filella, M; Berthon, G

    1992-07-01

    N-Acetyl-L-cysteine (NAC) has long been used in the treatment of chronic lung diseases. Inhalation and oral administration of the drug are both effective in reducing mucus viscosity. In addition, NAC oral therapy allows to restore normal mucoprotein secretion in the long term. Although displaying heavy metal-complexing potential, NAC exerts no detectable influence on the metabolism of essential trace metals when used in the above context (i.e. at doses near 600 mg day-1). However, this may no longer be the case when NAC is used as an oxygen radical scavenger, like in the treatment of paracetamol poisoning. In the latter case, intravenous doses as high as 20 g day-1 are administered, which may induce excessive zinc urinary excretion. In order to allow a better appreciation of the risk of zinc depletion during NAC therapy, the present work addresses the role of this drug towards zinc metabolism at the molecular level. First, formation constants for zinc-NAC complexes have been determined under physiological conditions. Then, computer simulations for blood plasma and gastrointestinal fluid have been run to assess the influence of NAC and its metabolites (e.g. cysteine and glutathione) on zinc excretion and absorption. Blood plasma simulations reveal that NAC can effectively mobilise an important fraction of zinc into urinary excretable complexes as from concentrations of 10(-3) mol dm-3 (which corresponds to a dose of about 800 mg). This effect can still be enhanced by the action of NAC metabolites, among which cysteine is the most powerful zinc sequestering agent. In contrast, simulations relative to gastrointestinal conditions suggest that NAC should tend to increase zinc absorption, regardless of its dose. PMID:1529808

  19. Electrospun Microfiber Scaffolds with Anti-Inflammatory Tributanoylated N-Acetyl-d-Glucosamine Promote Cartilage Regeneration.

    PubMed

    Kim, Chaekyu; Shores, Lucas; Guo, Qiongyu; Aly, Ahmed; Jeon, Ok Hee; Kim, Do Hun; Bernstein, Nicholas; Bhattacharya, Rahul; Chae, Jemin Jeremy; Yarema, Kevin J; Elisseeff, Jennifer H

    2016-04-01

    Tissue-engineering strategies offer promising tools for repairing cartilage damage; however, these strategies suffer from limitations under pathological conditions. As a model disease for these types of nonideal systems, the inflammatory environment in an osteoarthritic (OA) joint limits the efficacy of engineered therapeutics by disrupting joint homeostasis and reducing its capacity for regeneration. In this work, we investigated a sugar-based drug candidate, a tributanoylated N-acetyl-d-glucosamine analogue, called 3,4,6-O-Bu3GlcNAc, that is known to reduce nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling in osteoarthritis. 3,4,6-O-Bu3GlcNAc not only inhibited NFκB signaling but also exerted chondrogenic and anti-inflammatory effects on chondrocytes isolated from patients with osteoarthritis. 3,4,6-O-Bu3GlcNAc also increased the expression of extracellular matrix proteins and induced cartilage tissue production in three-dimensional in vitro hydrogel culture systems. To translate these chondrogenic and anti-inflammatory properties to tissue regeneration in osteoarthritis, we implanted 3,4,6-O-Bu3GlcNAc-loaded poly(lactic-co-glycolic acid) microfiber scaffolds into rats. The drug-laden scaffolds were biocompatible, and when seeded with human OA chondrocytes, similarly promoted cartilage tissue formation. 3,4,6-O-Bu3GlcNAc combined with the appropriate structural environment could be a promising therapeutic approach for osteoarthritis. PMID:27019285

  20. N-Acetyl L-Cysteine does not protect mouse ears from the effects of noise*

    PubMed Central

    2010-01-01

    Background Noise-induced hearing loss (NIHL) is one of the most common occupational injuries in the United States. It would be extremely valuable if a safe, inexpensive compound could be identified which protects worker hearing from noise. In a series of experiments, Kopke has shown that the compound N-acetyl-L-cysteine (L-NAC) can protect the hearing of chinchillas from the effects of a single exposure to noise. L-NAC is used in clinical medicine and is very safe. Although L-NAC was reported to be promising, it has not been successful in other studies (Kramer et al., 2006; Hamernik et al., 2008). The present study was undertaken to determine if L-NAC could protect C57BL/6J (B6) mice from the permanent effects of noise. Method Two groups of five B6 mice were injected with either 300 or 600 mg/kg L-NAC approximately 1 hr prior to a 104 dB broadband noise exposure and again immediately after the exposure. A control group (N = 7) was exposed to the same noise level but injected with vehicle (sterile saline). Auditory brainstem response measurements were made at 4, 8, 16 and 32 kHz one week prior to and 12 days after exposure. Conclusions There were no statistically significant differences in ABR threshold shifts between the mice receiving L-NAC and the control mice. This indicates that L-NAC was not effective in preventing permanent threshold shift in this mouse model of NIHL. PMID:20426871

  1. UDP-N-acetyl-α-d-galactosamine:polypeptide N-acetylgalactosaminyltransferases: Completion of the family tree

    PubMed Central

    Raman, Jayalakshmi; Guan, Yu; Perrine, Cynthia L; Gerken, Thomas A; Tabak, Lawrence A

    2012-01-01

    The formation of mucin-type O-glycans is initiated by an evolutionarily conserved family of enzymes, the UDP-N-acetyl-α-d-galactosamine:polypeptide N-acetylgalactosaminyltransferases (GalNAc-Ts). The human genome encodes 20 transferases; 17 of which have been characterized functionally. The complexity of the GalNAc-T family reflects the differential patterns of expression among the individual enzyme isoforms and the unique substrate specificities which are required to form the dense arrays of glycans that are essential for mucin function. We report the expression patterns and enzymatic activity of the remaining three members of the family and the further characterization of a recently reported isoform, GalNAc-T17. One isoform, GalNAcT-16 that is most homologous to GalNAc-T14, is widely expressed (abundantly in the heart) and has robust polypeptide transferase activity. The second isoform GalNAc-T18, most similar to GalNAc-T8, -T9 and -T19, completes a discrete subfamily of GalNAc-Ts. It is widely expressed and has low, albeit detectable, activity. The final isoform, GalNAc-T20, is most homologous to GalNAc-T11 but lacks a lectin domain and has no detectable transferase activity with the panel of substrates tested. We have also identified and characterized enzymatically active splice variants of GalNAc-T13 that differ in the sequence of their lectin domain. The variants differ in their affinities for glycopeptide substrates. Our findings provide a comprehensive view of the complexities of mucin-type O-glycan formation and provide insight into the underlying mechanisms employed to heavily decorate mucins and mucin-like domains with carbohydrate. PMID:22186971

  2. Debrisoquine 4-hydroxylation and sulphamethazine N-acetylation in patients with schizophrenia and major depression

    PubMed Central

    HADAŠOVÁ, EVA; FRANKE, GERD; ZSCHIESCHE, MICHAEL; ČEŠKOVÁ, EVA; ZELENKOVÁ, OLGA; SIEGMUND, WERNER

    1996-01-01

    Debrisoquine 4-hydroxylation and sulphamethazine N-acetylation phenotypes were determined in 115 Czech drug-free in-patients with schizophrenia (n=64) or major depressive disorder (n=51). These data were compared with a control group of 321 healthy volunteers from the North-East German area of Greifswald. The distribution of debrisoquine hydroxylator phenotypes was almost identical in patients and healthy controls. Thus, there were 8.7% (95% CI 5.4–12.0%) of poor metabolizers (PM) among patients while 8.7% (95% CI 3.6–13.8%) PM among the control group. The prevalences of PM amongst patients with chronic schizophrenia and major depression were 10.9% (95% CI 4.5–21.3%) and 5.9 % (95% CI 1.24–16.3%), respectively (χ2 schizophrenics vs control=0.315, NS; χ2 depressive patients vs control=0.450, NS). However, within the group of EM patients there was a significant (P<0.01) shift towards higher debrisoquine metabolic ratios, reflecting a lower hydroxylation capacity in EM patients compared with EM healthy controls. The proportion of slow acetylators (SA) was 60.0% (95% CI 51.0–68.9%) in the entire group of psychiatric patients and 57.5% (95% CI 52.1–62.9%) in the control group (χ2 all patients vs control=0.195, NS). Furthermore, there were no significant differences in the prevalence of the SA phenotype between controls and schizophrenics or patients with major depression. Although the results of this modest study were negative, the presence of subtle differences in the metabolic capacity between psychiatric patients and a healthy population cannot be ruled out. PMID:8735687

  3. Rapid successions affect microbial N-acetyl-glucosamine uptake patterns during a lacustrine spring phytoplankton bloom.

    PubMed

    Eckert, Ester M; Salcher, Michaela M; Posch, Thomas; Eugster, Bettina; Pernthaler, Jakob

    2012-03-01

    The vernal successions of phytoplankton, heterotrophic nanoflagellates (HNF) and viruses in temperate lakes result in alternating dominance of top-down and bottom-up factors on the bacterial community. This may lead to asynchronous blooms of bacteria with different life strategies and affect the channelling of particular components of the dissolved organic matter (DOM) through microbial food webs. We followed the dynamics of several bacterial populations and of other components of the microbial food web throughout the spring phytoplankton bloom period in a pre-alpine lake, and we assessed bacterial uptake patterns of two constituents of the labile DOM pool (N-acetyl-glucosamine [NAG] and leucine). There was a clear genotypic shift within the bacterial assemblage, from fast growing Cytophaga-Flavobacteria (CF) affiliated with Fluviicola and from Betaproteobacteria (BET) of the Limnohabitans cluster to more grazing resistant AcI Actinobacteria (ACT) and to filamentous morphotypes. This was paralleled by successive blooms of viruses and HNF. We also noted the transient rise of other CF (related to Cyclobacteriaceae and Sphingobacteriaceae) that are not detected by fluorescence in situ hybridization with the general CF probe. Both, the average uptake rates of leucine and the fractions of leucine incorporating bacteria were approximately five to sixfold higher than of NAG. However, the composition of the NAG-active community was much more prone to genotypic successions, in particular of bacteria with different life strategies: While 'opportunistically' growing BET and CF dominated NAG uptake in the initial period ruled by bottom-up factors, ACT constituted the major fraction of NAG active cells during the subsequent phase of high predation pressure. This indicates that some ACT could profit from a substrate that might in parts have originated from the grazing of protists on their bacterial competitors. PMID:22082109

  4. N-acetyl-L-cysteine and cysteine increase intracellular calcium concentration in human neutrophils

    PubMed Central

    Hasan, Md. Ashraful; Ahn, Won-Gyun

    2016-01-01

    N-acetyl-L-cysteine (NAC) and cysteine have been implicated in a number of human neutrophils' functional responses. However, though Ca2+ signaling is one of the key signalings contributing to the functional responses of human neutrophils, effects of NAC and cysteine on intracellular calcium concentration ([Ca2+]i) in human neutrophils have not been investigated yet. Thus, this study was carried out with an objective to investigate the effects of NAC and cysteine on [Ca2+]i in human neutrophils. We observed that NAC (1 µM ~ 1 mM) and cysteine (10 µM ~ 1 mM) increased [Ca2+]i in human neutrophils in a concentration-dependent manner. In NAC pre-supplmented buffer, an additive effect on N-formyl-methionine-leucine-phenylalanine (fMLP)-induced increase in [Ca2+]i in human neutrophils was observed. In Ca2+-free buffer, NAC- and cysteine-induced [Ca2+]i increase in human neutrophils completely disappeared, suggesting that NAC- and cysteine-mediated increase in [Ca2+]i in human neutrophils occur through Ca2+ influx. NAC- and cysteine-induced [Ca2+]i increase was effectively inhibited by calcium channel inhibitors SKF96365 (10 µM) and ruthenium red (20 µM). In Na+-free HEPES, both NAC and cysteine induced a marked increase in [Ca2+]i in human neutrophils, arguing against the possibility that Na+-dependent intracellular uptake of NAC and cysteine is necessary for their [Ca2+]i increasing activity. Our results show that NAC and cysteine induce [Ca2+]i increase through Ca2+ influx in human neutrophils via SKF96365- and ruthenium red-dependent way. PMID:27610031

  5. N-acetyl-L-cysteine and cysteine increase intracellular calcium concentration in human neutrophils.

    PubMed

    Hasan, Md Ashraful; Ahn, Won-Gyun; Song, Dong-Keun

    2016-09-01

    N-acetyl-L-cysteine (NAC) and cysteine have been implicated in a number of human neutrophils' functional responses. However, though Ca(2+) signaling is one of the key signalings contributing to the functional responses of human neutrophils, effects of NAC and cysteine on intracellular calcium concentration ([Ca(2+)]i) in human neutrophils have not been investigated yet. Thus, this study was carried out with an objective to investigate the effects of NAC and cysteine on [Ca(2+)]i in human neutrophils. We observed that NAC (1 µM ~ 1 mM) and cysteine (10 µM ~ 1 mM) increased [Ca(2+)]i in human neutrophils in a concentration-dependent manner. In NAC pre-supplmented buffer, an additive effect on N-formyl-methionine-leucine-phenylalanine (fMLP)-induced increase in [Ca(2+)]i in human neutrophils was observed. In Ca(2+)-free buffer, NAC- and cysteine-induced [Ca(2+)]i increase in human neutrophils completely disappeared, suggesting that NAC- and cysteine-mediated increase in [Ca(2+)]i in human neutrophils occur through Ca(2+) influx. NAC- and cysteine-induced [Ca(2+)]i increase was effectively inhibited by calcium channel inhibitors SKF96365 (10 µM) and ruthenium red (20 µM). In Na(+)-free HEPES, both NAC and cysteine induced a marked increase in [Ca(2+)]i in human neutrophils, arguing against the possibility that Na(+)-dependent intracellular uptake of NAC and cysteine is necessary for their [Ca(2+)]i increasing activity. Our results show that NAC and cysteine induce [Ca(2+)]i increase through Ca(2+) influx in human neutrophils via SKF96365- and ruthenium red-dependent way. PMID:27610031

  6. N-Acetyl-β-D-glucosaminidase activity in feral Carcinus maenas exposed to cadmium.

    PubMed

    Mesquita, Sofia Raquel; Ergen, Şeyda Fikirdeşici; Rodrigues, Aurélie Pinto; Oliva-Teles, M Teresa; Delerue-Matos, Cristina; Guimarães, Laura

    2015-02-01

    Cadmium is a priority hazardous substance, persistent in the aquatic environment, with the capacity to interfere with crustacean moulting. Moulting is a vital process dictating crustacean growth, reproduction and metamorphosis. However, for many organisms, moult disruption is difficult to evaluate in the short term, what limits its inclusion in monitoring programmes. N-acetyl-β-D-glucosaminidase (NAGase) is an enzyme acting in the final steps of the endocrine-regulated moulting cascade, allowing for the cast off of the old exoskeleton, with potential interest as a biomarker of moult disruption. This study investigated responses to waterborne cadmium of NAGase activity of Carcinus maenas originating from estuaries with different histories of anthropogenic contamination: a low impacted and a moderately polluted one. Crabs from both sites were individually exposed for seven days to cadmium concentrations ranging from 1.3 to 2000 μg/L. At the end of the assays, NAGase activity was assessed in the epidermis and digestive gland. Detoxification, antioxidant, energy production, and oxidative stress biomarkers implicated in cadmium metabolism and tolerance were also assessed to better understand differential NAGase responses: activity of glutathione S-transferases (GST), glutathione peroxidase (GPx) glutathione reductase (GR), levels of total glutathiones (TG), lipid peroxidation (LPO), lactate dehydrogenase (LDH), and NADP(+)-dependent isocitrate dehydrogenase (IDH). Animals from the moderately polluted estuary had lower NAGase activity both in the epidermis and digestive gland than in the low impacted site. NAGase activity in the epidermis and digestive gland of C. maenas from both estuaries was sensitive to cadmium exposure suggesting its usefulness for inclusion in monitoring programmes. However, in the digestive gland NAGase inhibition was found in crabs from the less impacted site but not in those from the moderately contaminated one. Altered glutathione levels were

  7. Co-Administration of Metformin and N-Acetyl Cysteine Fails to Improve Clinical Manifestations in PCOS Individual Undergoing ICSI

    PubMed Central

    Cheraghi, Ebrahim; Soleimani Mehranjani, Malek; Shariatzadeh, Mohammad Ali; Nasr Esfahani, Mohammad Hossein; Ebrahimi, Zahra

    2014-01-01

    Background Studies have demonstrated the efficacy of metformin (MTF ) in reducing insulin resistance and N-acetyl cysteine (NAC) in inhibiting oxidative stress which are involved in the pathogenesis of polycystic ovarian syndrome (PCOS). We aimed to compare the effects of MTF and NAC combination on serum metabolite and hormonal levels during the course of ovulation induction in PCOS individual candidates of intracytoplasmic sperm injection (ICSI). Materials and Methods In this prospective randomized clinical trial, placebo con- trolled pilot study, 80 patients of polycystic ovarian syndrome at the age of 25-35 years were divided into 4 groups (n=20): i. NAC=treated with N-acetyl cysteine (600 mg three times daily), ii. MTF=treated with metformin (500 mg three times daily), iii. MTF+NAC=treated with N-acetyl cysteine plus metformin (the offered doses) and iv. placebo (PLA). A total number of 20 patients (6 from MTF group, 4 from NAC group, 6 from MTF+NAC group and 4 from PLA group) were dropped of the study. The drugs were administrated from day 3 of menses of previous cycle until ovum pick-up. Results Serum levels of luteinizing hormone (LH), total testosterone, cholester- ol and triglyceride, insulin and leptin significantly reduced in the MTF and NAC groups compared to the placebo (p<0.01). But levels of LH, total testosterone, cholesterol and triglyceride had no significant reduction in the MTF+NAC groups compared to the placebo. The serum levels of malonyldialdehyde (MDA), insulin and leptin reduced significantly after treatment in the MTF+NAC group compared to the placebo (p<0.05). Conclusion Considering the adverse effect of combination therapy, we proposed the conadministration might have no beneficial effect for PCOS patient during course of ovulation induction of ICSI (Registration Number: IRCT201204159476N1). PMID:25083175

  8. In vitro susceptibility of Scedosporium isolates to N-acetyl-L-cysteine alone and in combination with conventional antifungal agents.

    PubMed

    Homa, Mónika; Galgóczy, László; Tóth, Eszter; Virágh, Máté; Chandrasekaran, Muthusamy; Vágvölgyi, Csaba; Papp, Tamás

    2016-10-01

    In recent years, Scedosporium species have been more commonly recognized from severe, difficult-to-treat human infections, such as upper respiratory tract and pulmonary infections. To select an appropriate therapeutic approach for these infections is challenging, because of the commonly observed resistance of the causative agents to several antifungal drugs. Therefore, to find a novel strategy for the treatment of pulmonary Scedosporium infections the in vitro antifungal effect of a mucolytic agent, N-acetyl-L-cysteine and its in vitro combinations with conventional antifungals were investigated. Synergistic and indifferent interactions were registered in 23 and 13 cases, respectively. Antagonism was not revealed between the compounds. PMID:27143635

  9. Crystal Structure of the N-Acetyltransferase Domain of Human N-Acetyl-L-Glutamate Synthase in Complex with N-Acetyl-L-Glutamate Provides Insights into Its Catalytic and Regulatory Mechanisms

    PubMed Central

    Zhao, Gengxiang; Jin, Zhongmin; Allewell, Norma M.; Tuchman, Mendel; Shi, Dashuang

    2013-01-01

    N-acetylglutamate synthase (NAGS) catalyzes the conversion of AcCoA and L-glutamate to CoA and N-acetyl-L-glutamate (NAG), an obligate cofactor for carbamyl phosphate synthetase I (CPSI) in the urea cycle. NAGS deficiency results in elevated levels of plasma ammonia which is neurotoxic. We report herein the first crystal structure of human NAGS, that of the catalytic N-acetyltransferase (hNAT) domain with N-acetyl-L-glutamate bound at 2.1 Å resolution. Functional studies indicate that the hNAT domain retains catalytic activity in the absence of the amino acid kinase (AAK) domain. Instead, the major functions of the AAK domain appear to be providing a binding site for the allosteric activator, L-arginine, and an N-terminal proline-rich motif that is likely to function in signal transduction to CPS1. Crystalline hNAT forms a dimer similar to the NAT-NAT dimers that form in crystals of bifunctional N-acetylglutamate synthase/kinase (NAGS/K) from Maricaulis maris and also exists as a dimer in solution. The structure of the NAG binding site, in combination with mutagenesis studies, provide insights into the catalytic mechanism. We also show that native NAGS from human and mouse exists in tetrameric form, similar to those of bifunctional NAGS/K. PMID:23894642

  10. Crystal structure of the N-acetyltransferase domain of human N-acetyl-L-glutamate synthase in complex with N-acetyl-L-glutamate provides insights into its catalytic and regulatory mechanisms.

    PubMed

    Zhao, Gengxiang; Jin, Zhongmin; Allewell, Norma M; Tuchman, Mendel; Shi, Dashuang

    2013-01-01

    N-acetylglutamate synthase (NAGS) catalyzes the conversion of AcCoA and L-glutamate to CoA and N-acetyl-L-glutamate (NAG), an obligate cofactor for carbamyl phosphate synthetase I (CPSI) in the urea cycle. NAGS deficiency results in elevated levels of plasma ammonia which is neurotoxic. We report herein the first crystal structure of human NAGS, that of the catalytic N-acetyltransferase (hNAT) domain with N-acetyl-L-glutamate bound at 2.1 Å resolution. Functional studies indicate that the hNAT domain retains catalytic activity in the absence of the amino acid kinase (AAK) domain. Instead, the major functions of the AAK domain appear to be providing a binding site for the allosteric activator, L-arginine, and an N-terminal proline-rich motif that is likely to function in signal transduction to CPS1. Crystalline hNAT forms a dimer similar to the NAT-NAT dimers that form in crystals of bifunctional N-acetylglutamate synthase/kinase (NAGS/K) from Maricaulis maris and also exists as a dimer in solution. The structure of the NAG binding site, in combination with mutagenesis studies, provide insights into the catalytic mechanism. We also show that native NAGS from human and mouse exists in tetrameric form, similar to those of bifunctional NAGS/K. PMID:23894642

  11. Influence of pigments and pH of urine on the determination of N-acetyl-beta-D-glucosaminidase activity with 2-methoxy-4-(2'-nitrovinyl)-phenyl-N-acetyl-beta-D-glucosaminide.

    PubMed

    Aćimović, Jelena M; Jovanović, Vesna B; Mandić, Ljuba M

    2005-01-01

    The influence of urinary pigments and urine pH on the spectrophotometric determination of N-acetyl-beta-D-glucosaminidase (NAG; EC 3.2.1.30) activity with 2-methoxy-4-(2'-nitrovinyl)-phenyl-N-acetyl-beta-D-glucosaminide as a substrate was studied. The investigation was performed with human and rabbit urine samples. It was found that alkaline urine pH values influenced NAG activity in two ways: 1) NAG activity decreased due to enzyme instability with pH increase, and 2) NAG activity increased because of the contribution of urinary pigments to absorbance of 2-methoxy-4-(2'-nitrovinyl)-phenol (MNP) at 505 nm. It was shown that besides the maximum (I) in the range of 350-360 nm of the absorption spectra of alkaline urine, there was a maximum (II) in the range of 380-460 nm. With the increase of pH, maximum II was shifted toward higher wavelengths and contributed to MNP absorption (5-90%). On the other hand, the maximum of MNP absorption was shifted toward lower wavelengths (495-400 nm) with increasing pH. Two procedures to eliminate the influence of urinary pigments are presented. The justification of applying a correction to the values of NAG activity in human and rabbit urine (a model system for studying the toxic effects of cadmium) was discussed. PMID:16302206

  12. Structure of the complex of Neisseria gonorrhoeae N-acetyl-L-glutamate synthase with a bound bisubstrate analog.

    PubMed

    Zhao, Gengxiang; Allewell, Norma M; Tuchman, Mendel; Shi, Dashuang

    2013-01-25

    N-Acetyl-L-glutamate synthase catalyzes the conversion of AcCoA and glutamate to CoA and N-acetyl-L-glutamate (NAG), the first step of the arginine biosynthetic pathway in lower organisms. In mammals, NAG is an obligate cofactor of carbamoyl phosphate synthetase I in the urea cycle. We have previously reported the structures of NAGS from Neisseria gonorrhoeae (ngNAGS) with various substrates bound. Here we reported the preparation of the bisubstrate analog, CoA-S-acetyl-L-glutamate, the crystal structure of ngNAGS with CoA-NAG bound, and kinetic studies of several active site mutants. The results are consistent with a one-step nucleophilic addition-elimination mechanism with Glu353 as the catalytic base and Ser392 as the catalytic acid. The structure of the ngNAGS-bisubstrate complex together with the previous ngNAGS structures delineates the catalytic reaction path for ngNAGS. PMID:23261468

  13. Structure of the complex of Neisseria gonorrhoeae N-acetyl-L-glutamate synthase with a bound bisubstrate analog

    PubMed Central

    ZHAO, GENGXIANG; ALLEWELL, NORMA M.; TUCHMAN, MENDEL; SHI, DASHUANG

    2013-01-01

    N -acetyl-L-glutamate synthase catalyzes the conversion of AcCoA and glutamate to CoA and N-acetyl-L-glutamate (NAG), the first step of the arginine biosynthetic pathway in lower organisms. In mammals, NAG is an obligate cofactor of carbamoyl phosphate synthetase I in the urea cycle. We have previously reported the structures of NAGS from Neisseria gonorrhoeae (ngNAGS) with various substrates bound. Here we reported the preparation of the bisubstrate analog, CoA-S-acetyl-L-glutamate, the crystal structure of ngNAGS with CoA-NAG bound, and kinetic studies of several active site mutants. The results are consistent with a one-step nucleophilic addition-elimination mechanism with Glu353 as the catalytic base and Ser392 as the catalytic acid. The structure of the ngNAGS-bisubstrate complex together with the previous ngNAGS structures delineates the catalytic reaction path for ngNAGS. PMID:23261468

  14. Microwave-Assisted Esterification of N-Acetyl-L-Phenylalanine Using Modified Mukaiyama's Reagents: A New Approach Involving Ionic Liquids

    PubMed Central

    Zhao, Hua; Song, Zhiyan; Cowins, Janet V.; Olubajo, Olarongbe

    2008-01-01

    Inspired by the concept of ionic liquids (ILs), this study modified the original Mukaiyama's reagent, 2-chloro-1-methylpyridinium iodide (m.p. 200-dec), from ionic solid into liquids by changing its anion. The esterification of N-acetyl-L-phenylalanine was investigated as a model reaction. The microwave irradiation was more effective in esterifying N-acetyl-L-phenylalanine than the conventional reflux method. The original Mukaiyama's reagent was modified into ILs through manipulating its anion. However, only non-nucleophilic anions (such as EtSO4– and Tf2N–) were favorable since nucleophilic ones (such as CF3COO– and CH3COO–) could exchange with chlorine resulting in non-reactive coupling reagents. Two modified Mukaiyama's compounds (i.e. hydrophilic [2-ClMePy][EtSO4] and hydrophobic [2-ClMePy][Tf2N]) have been identified as the best ILtype coupling reagents. The esterification reaction was greatly enhanced by using 1- methylimidazole as the base instead of conventional toxic tertiary amines, and by using excess amount of alcohols as solvents instead of dichloromethane. Overall, the method reported is effective and ‘greener’. PMID:19325717

  15. Hydrosoluble 50% N-acetylation-thiolated chitosan complex with cobalt as a pH-responsive renal fibrosis targeting drugs.

    PubMed

    Li, Min; Tan, Lishan; Tang, Liangfeng; Li, Aiqing; Hu, Jianqiang

    2016-07-01

    About 50% N-acetylation-thiolated chitosan possessing good water solubility was modified from commercial low-molecular-weight chitosan. Chitosan performed obvious target toward renal tubular epithelial cells, and bivalent cobalt ions improved the renal fibrosis inflammation significantly. There were many complexation sites on chitosan after being modified with sulfydryl. So sulfydryl played a role of connecting bridge between chitosan and cobalt ions. Then, this N-acetylation-thiolated chitosan cobalt (NTCC) nanocomplex was designed. The nanocomplex showed excellent stability under normal physiological conditions, and cobalt would be released from the biomaterials in acidic environment. As it was affected by inflammation, the pH in renal fibrosis lesion region was acidic. So there was a specific drug release process happening in lesion region. And drug release efficiency was determined by acidity, which demonstrated that lower the acidity, the faster and more the cobalt ion release. When this nanocomplex was intraperitoneally injected into ureter-obstructed mice, obvious attenuation of fibrotic progression was shown. It was demonstrated that NTCC exhibited special renal-targeting capacity and could be chosen as drug for treating renal fibrosis. PMID:27115330

  16. Involvement of N-acetyl-lactosamine-containing sugar structures in the liver metastasis of mouse colon carcinoma (colon 26) cells.

    PubMed

    Kawakami, H; Ito, M; Miura, Y; Hirano, H

    1994-01-01

    Histochemical aspects of the process of experimentally induced metastasis were examined by light and electron microscopy with labelled lectins employed as a probe. Mouse colon carcinoma cells (colon 26) were injected into the spleen of Balb/c mice and liver metastasis was induced. Among the lectins tested, Erythrina cristagalli agglutinin (ECA) stained the metastasized colon 26 cells strongly compared with the heterogeneous and faint staining in non-metastasized tumour foci in the spleen or in the subcutaneous space. Other lectins, such as Phaseolus vulgaris leucoagglutinin (PHA-L), Phaseolus vulgaris erythroagglutinin (PHA-E) and Datura stramonium agglutinin (DSA), having specificity for branched complex type sugar chains, did not show any differences between metastasized cells and non-metastasized tumour foci. In addition, N-acetyl-lactosamine, a specific inhibitor of ECA binding, significantly inhibited the attachment of suspended colon 26 cells to sectioned unfixed normal liver tissue. These results indicate that the expression of galactose (Gal) beta 1-4 N-acetyl-glucosamine (GlcNAc) residues of branched complex type sugar chains having specificity for ECA are important for the interaction process of carcinoma cells with hepatic cells in the process of liver metastasis. PMID:7532448

  17. Affinity Separation of Lectins Using Porous Membranes Immobilized with Glycopolymer Brushes Containing Mannose or N-Acetyl-d-Glucosamine

    PubMed Central

    Ogata, Yutaro; Seto, Hirokazu; Murakami, Tatsuya; Hoshino, Yu; Miura, Yoshiko

    2013-01-01

    Porous membranes with glycopolymer brushes were prepared as biomaterials for affinity separation. Glycopolymer brushes contained acrylic acid and D-mannose or N-acetyl-D-glucosamine, and were formed on substrates by surface-initiated atom transfer radical polymerization. The presence of glycopolymer brush was confirmed by X-ray photoelectron spectroscopy, contact angle, and ellipsometry measurements. The interaction between lectin and the glycopolymer immobilized on glass slides was confirmed using fluorescent-labeled proteins. Glycopolymer-immobilized surfaces exhibited specific adsorption of the corresponding lectin, compared with bovine serum albumin. Lectins were continuously rejected by the glycopolymer-immobilized membranes. When the protein solution was permeated through the glycopolymer-immobilized membrane, bovine serum albumin was not adsorbed on the membrane surface. In contrast, concanavalin A and wheat germ agglutinin were rejected by membranes incorporating D-mannose or N-acetyl-D-glucosamine, respectively. The amounts of adsorbed concanavalin A and wheat germ agglutinin was increased five- and two-fold that of adsorbed bovine serum albumin, respectively. PMID:24956944

  18. N-Acetylation of p-aminobenzoic acid and p-phenylenediamine in primary porcine urinary bladder epithelial cells and in the human urothelial cell line 5637.

    PubMed

    Föllmann, Wolfram; Blaszkewicz, Meinolf; Behm, Claudia; Degen, Gisela H; Golka, Klaus

    2012-01-01

    N-Acetyltransferases (NAT) are important enzymes in the metabolism of certain carcinogenic arylamines, as N-acetylation decreases or prevents their bioactivation via N-hydroxylation. To study such processes in the bladder, cell culture models may be used, but metabolic competence needs to be characterized. This study focused on the N-acetylation capacity of two urothelial cell systems, using p-aminobenzoic acid (PABA) and the hair dye precursor p-phenylenediamine (PPD), two well-known substrates of the enzyme NAT1. The constitutive NAT1 activity was investigated using primary cultures of porcine urinary bladder epithelial cells (PUBEC) and in the human urothelial cell line 5637 to assess their suitability for further in vitro studies on PABA and PPD-induced toxicity. N-Acetylation of PABA and PPD was determined by high-performance liquid chromatography (HPLC) analysis in cytosols of the two cell systems upon incubation with various substrate levels for up to 60 min. The primary PUBEC revealed higher N-acetylation rates (2.5-fold for PABA, 5-fold for PPD) compared to the 5637 cell line, based on both PABA conversion to its acetylated metabolite and formation of mono- and diacetylated PPD. The urothelial cell systems may thus be useful as a tool for further studies on the N-acetylation of aromatic amines via NAT1. PMID:22994574

  19. Amodiaquine-induced toxicity in isolated rat hepatocytes and the cytoprotective effects of taurine and/or N-acetyl cysteine.

    PubMed

    Heidari, R; Babaei, H; Eghbal, M A

    2014-01-01

    Amodiaquine is an antimalarial drug used in the prophylaxis and treatment of this disease. However, hepatotoxicity as a life-threatening adverse effect is associated with its clinical use. We evaluated amodiaquine-induced toxicity in isolated rat hepatocytes as an in vitro model for studying drug-induced hepatotoxicity. This study attempts to investigate the protective effects of taurine and N-acetyl cysteine against the cytotoxicity induced by amodiaquine. Hepatocytes were prepared by the method of collagenase enzyme perfusion via portal vein. This technique is based on liver perfusion with collagenase after removal of calcium ion (Ca(2+)) with a chelator (ethylene glycol tetraacetic acid (EGTA) 0.5 mM). Cells were treated with different concentrations of amodiaquine, taurine and N-acetyl cysteine. Cell death, protein carbonylation, reactive oxygen species formation, lipid peroxidation, and mitochondrial depolarization were assessed as toxicity markers. Amodiaquine cytotoxic mechanism involved protein carbonylation as well as reactive oxygen species formation and lipid peroxidation. In addition, mitochondria seem to be a target for amodiaquine to induce cellular damage. Administration of taurine (200 μM) and/or N-acetyl cysteine (200 μM) reduced oxidative stress, lipid peroxidation and protein carbonylation caused by amodiaquine. Furthermore, amodiaquine-induced mitochondrial injury was significantly mitigated by taurine and/or N-acetyl cysteine. In glutathione-depleted cells, only N-acetyl cysteine protected hepatocytes against amodiaquine, and taurine showed no protective properties in this situation. Taurine and N-acetyl cysteine protect hepatocytes against amodiaquine probably via their antioxidant properties and counteracting oxidative stress. PMID:25657778

  20. Structures of the N-acetyltransferase domain of Xylella fastidiosa N-acetyl-l-glutamate synthase/kinase with and without a His tag bound to N-acetyl-l-glutamate

    PubMed Central

    Zhao, Gengxiang; Jin, Zhongmin; Allewell, Norma M.; Tuchman, Mendel; Shi, Dashuang

    2015-01-01

    Structures of the catalytic N-acetyltransferase (NAT) domain of the bifunctional N-acetyl-l-glutamate synthase/kinase (NAGS/K) from Xylella fastidiosa bound to N-acetyl-l-glutamate (NAG) with and without an N-terminal His tag have been solved and refined at 1.7 and 1.4 Å resolution, respectively. The NAT domain with an N-terminal His tag crystallized in space group P41212, with unit-cell parameters a = b = 51.72, c = 242.31 Å. Two subunits form a molecular dimer in the asymmetric unit, which contains ∼41% solvent. The NAT domain without an N-terminal His tag crystallized in space group P21, with unit-cell parameters a = 63.48, b = 122.34, c = 75.88 Å, β = 107.6°. Eight subunits, which form four molecular dimers, were identified in the asymmetric unit, which contains ∼38% solvent. The structures with and without the N-terminal His tag provide an opportunity to evaluate how the His tag affects structure and function. Furthermore, multiple subunits in different packing environments allow an assessment of the plasticity of the NAG binding site, which might be relevant to substrate binding and product release. The dimeric structure of the X. fastidiosa N-acetytransferase (xfNAT) domain is very similar to that of human N-acetyltransferase (hNAT), reinforcing the notion that mammalian NAGS is evolutionally derived from bifunctional bacterial NAGS/K. PMID:25615976

  1. Structures of the N-acetyltransferase domain of Xylella fastidiosa N-acetyl-L-glutamate synthase/kinase with and without a His tag bound to N-acetyl-L-glutamate.

    PubMed

    Zhao, Gengxiang; Jin, Zhongmin; Allewell, Norma M; Tuchman, Mendel; Shi, Dashuang

    2015-01-01

    Structures of the catalytic N-acetyltransferase (NAT) domain of the bifunctional N-acetyl-L-glutamate synthase/kinase (NAGS/K) from Xylella fastidiosa bound to N-acetyl-L-glutamate (NAG) with and without an N-terminal His tag have been solved and refined at 1.7 and 1.4 Å resolution, respectively. The NAT domain with an N-terminal His tag crystallized in space group P4(1)2(1)2, with unit-cell parameters a=b=51.72, c=242.31 Å. Two subunits form a molecular dimer in the asymmetric unit, which contains ∼41% solvent. The NAT domain without an N-terminal His tag crystallized in space group P21, with unit-cell parameters a=63.48, b=122.34, c=75.88 Å, β=107.6°. Eight subunits, which form four molecular dimers, were identified in the asymmetric unit, which contains ∼38% solvent. The structures with and without the N-terminal His tag provide an opportunity to evaluate how the His tag affects structure and function. Furthermore, multiple subunits in different packing environments allow an assessment of the plasticity of the NAG binding site, which might be relevant to substrate binding and product release. The dimeric structure of the X. fastidiosa N-acetytransferase (xfNAT) domain is very similar to that of human N-acetyltransferase (hNAT), reinforcing the notion that mammalian NAGS is evolutionally derived from bifunctional bacterial NAGS/K. PMID:25615976

  2. Identifying dominant conformations of N-acetyl-L-cysteine methyl ester and N-acetyl-L-cysteine in water: VCD signatures of the amide I and the Cdbnd O stretching bands

    NASA Astrophysics Data System (ADS)

    Poopari, Mohammad Reza; Dezhahang, Zahra; Xu, Yunjie

    2015-02-01

    Infrared (IR) and vibrational circular dichroism (VCD) spectra of N-Acetyl-L-Cysteine Methyl Ester (NALCME) and N-Acetyl-L-Cysteine (NALC) in D2O under different pHs were measured. We focus on the VCD signatures of the amide I and the Cdbnd O stretching spectral signatures of the neutral NALCME and NALC species and the related ones of the deprotonated NALC species in the region of 1800-1500 cm-1. A sign inversion is observed for the amide I VCD band going from the neutral NALCME and NALC to the deprotonated NALC species. Density functional theory (DFT) calculations were carried out to search for the possible conformations of these three species and to simulate their IR and VCD spectra at the B3LYP/aug-cc-pVTZ level in the gas phase and with the polarization continuum model of water solvent. The most stable conformations found for neutral NALCME and NALC exhibit drastically difference VCD patterns, whereas those of deprotonated NALC show similar patterns. We establish an empirical structural-spectral relationship where the aforementioned VCD signatures can be used as spectral markers to identify dominant conformations of these two amino acid derivatives under different pHs. It is recognized that the dominant conformers identified using the VCD spectral markers differ from those based on the relative DFT energies for neutral NALCME and NALC. The influence of solvent on both the conformational geometries and their relative stabilities is discussed. The aforementioned discrepancy can be attributed to the explicit solute-solvent hydrogen-bonding interactions which are not accounted for in the calculations. The empirical structural-spectral relationship identified can potentially be applied to large, related amino acids and polypeptides in water.

  3. Synthesis and immunological evaluation of MUC1 glycopeptide conjugates bearing N-acetyl modified STn derivatives as anticancer vaccines.

    PubMed

    Xiao, An; Zheng, Xiu-Jing; Song, Chengcheng; Gui, Yue; Huo, Chang-Xin; Ye, Xin-Shan

    2016-07-26

    Glycoprotein MUC1 is an attractive target for anti-tumor vaccine development. However, the weak immunogenicity of MUC1 remains a significant problem. To solve this problem, several STn derivatives with N-acetyl modifications were synthesized and incorporated into a 20-amino acid MUC1 tandem repeat sequence. The modified STn-MUC1 glycopeptides were further connected to a carrier protein keyhole limpet hemocyanin (KLH). The immunological effects of these synthetic vaccine conjugates were evaluated using the BALB/c mouse model. The results showed that vaccine V2 elicited higher titers of antibodies which cross-reacted with the native STn-MUC1 antigen. Moreover, the elicited antisera reacted with the STn-MUC1 antigen-positive tumor cells, indicating that the carbohydrate antigen modification strategy may hold potential to overcome the weak immunogenicity of natural MUC1 glycopeptides. PMID:27380866

  4. The tetrapeptide N-acetyl-Pro-Pro-Tyr-Leu in skin care formulations-Physicochemical and release studies.

    PubMed

    Olejnik, Anna; Schroeder, Grzegorz; Nowak, Izabela

    2015-08-15

    Recently there has been a growth of interest in the novel skin care formulations containing active ingredients such as low molecular weight peptides. In this paper we present new skincare formulations such as hydrogels, oil-in-water emulsions and water-in-oil emulsion containing a tetrapeptide (N-acetyl-Pro-Pro-Tyr-Leu). These formulations were characterized in terms of physicochemical parameters (pH, viscosity), stability and particle size distribution. Additionally, the diffusion parameters of the peptide in the obtained formulations were calculated based on the Einstein-Smoluchowski equation. Furthermore, in order to determine the penetration of the tetrapeptide through membranes its release kinetics were investigated. On the basis of release curves, the release rate constants were determined. The results proved that the properties of the formulations strongly determined the release rate of the tetrapeptide. The higher viscosity of the semisolid, the slower was the permeation through the membrane. PMID:26188319

  5. Protective effect of N-acetyl-L-cysteine against disulfiram-induced oxidative stress and apoptosis in V79 cells

    SciTech Connect

    Grosicka-Maciag, Emilia; Kurpios-Piec, Dagmara; Grzela, Tomasz; Czeczot, Hanna; Skrzycki, Michal; Szumilo, Maria; Rahden-Staron, Iwonna

    2010-11-01

    This work investigated the effect of N-acetyl-L-cysteine (NAC) on disulfiram (DSF) induced oxidative stress in Chinese hamster fibroblast cells (V79). An increase in oxidative stress induced by DSF was observed up to a 200 {mu}M concentration. It was evidenced by a statistically significant increase of both GSH{sub t} and GSSG levels, as well as elevated protein carbonyl (PC) content. There was no increase in lipid peroxidation (measured as TBARS). DSF increased CAT activity, but did not change SOD1 and SOD2 activities. Analysis of GSH related enzymes showed that DSF significantly increased GR activity, did not change Se-dependent GPx, but statistically significantly decreased non-Se-dependent GPx activity. DSF showed also pro-apoptotic activity. NAC alone did not produce any significant changes, besides an increase of GSH{sub t} level, in any of the variables measured. However, pre-treatment of cells with NAC ameliorated DSF-induced changes. NAC pre-treatment restored the viability of DSF-treated cells evaluated by Trypan blue exclusion assay and MTT test, GSSG level, and protein carbonyl content to the control values as well as it reduced pro-apoptotic activity of DSF. The increase of CAT and GR activity was not reversed. Activity of both GPx was significantly increased compared to their values after DSF treatment. In conclusion, oxidative properties are at least partially attributable to the cellular effects of disulfiram and mechanisms induced by NAC pre-treatment may lower or even abolish the observed effects. These observations illustrate the importance of the initial cellular redox state in terms of cell response to disulfiram exposure. -- Research Highlights: {yields}This report explores biological properties of disulfiram under a condition of modulated intra-cellular GSH level. It shows a protective role of N-acetyl-L-cysteine in V79 cells exposed to disulfiram (in GSH metabolism as well as in changes of antioxidant enzyme activity).

  6. Two crystal structures of Escherichia coli N-acetyl-L-glutamate kinase demonstrate the cycling between open and closed conformations.

    PubMed

    Gil-Ortiz, Fernando; Ramón-Maiques, Santiago; Fernández-Murga, María L; Fita, Ignacio; Rubio, Vicente

    2010-06-11

    N-Acetyl-L-glutamate kinase (NAGK), the paradigm enzyme of the amino acid kinase family, catalyzes the second step of arginine biosynthesis. Although substrate binding and catalysis were clarified by the determination of four crystal structures of the homodimeric Escherichia coli enzyme (EcNAGK), we now determine 2 A resolution crystal structures of EcNAGK free from substrates or complexed with the product N-acetyl-L-glutamyl-5-phosphate (NAGP) and with sulfate, which reveal a novel, very open NAGK conformation to which substrates would associate and from which products would dissociate. In this conformation, the C-domain, which hosts most of the nucleotide site, rotates approximately 24 degrees -28 degrees away from the N-domain, which hosts the acetylglutamate site, whereas the empty ATP site also exhibits some changes. One sulfate is found binding in the region where the beta-phosphate of ATP normally binds, suggesting that ATP is first anchored to the beta-phosphate site, before perfect binding by induced fit, triggering the shift to the closed conformation. In contrast, the acetylglutamate site is always well formed, although its beta-hairpin lid is found here to be mobile, being closed only in the subunit of the EcNAGK-NAGP complex that binds NAGP most strongly. Lid closure appears to increase the affinity for acetylglutamate/NAGP and to stabilize the closed enzyme conformation via lid-C-domain contacts. Our finding of NAGP bound to the open conformation confirms that this product dissociates from the open enzyme form and allows reconstruction of the active center in the ternary complex with both products, delineating the final steps of the reaction, which is shown here by site-directed mutagenesis to involve centrally the invariant residue Gly11. PMID:20403363

  7. N-Acetyl-L-Cysteine abrogates fibrogenic properties of fibroblasts isolated from Dupuytren's disease by blunting TGF-β signalling

    PubMed Central

    Kopp, Jürgen; Seyhan, Harun; Müller, Bastian; Lanczak, Johanna; Pausch, Elke; Gressner, Axel M; Dooley, Steven; Horch, Raymund E

    2006-01-01

    Dupuytren's disease, a benign fibroproliferative disorder of the palmar fascia, represents an ideal model to study tissue fibrosis. Transforming growth factor-β1 (TGF-β1) and its downstream Smad signalling system is well established as a key player during fibrogenesis. Thus, targeting this basic pathomechanism seems suitable to establish new treatment strategies. One such promising treatment involves the substance N-acetyl-L-cysteine (NAC), shown to have antifibrotic properties in hepatic stellate cells and rat fibroblasts. In order to investigate antifibrotic effects of N-acetyl-L-cysteine (NAC), fibroblasts were isolated from surgically resected fibrotic palmar tissues (Dupuytren fibroblasts, DF) and exposed to different concentrations of NAC and recombinant TGF-β1. Fibroblasts isolated from tendon pulleys served as controls (control fibroblasts, CF). Smad signalling was investigated by a Smad binding element driven reporter gene analysis. Both cell types express TGF-β1, indicating autocrine signalling in DF and CF. This was confirmed by comparing reporter gene activity from LacZ and Smad7 adenovirus infected cells. NAC treatment resulted in abrogation of Smad mediated signalling comparable to ectopically overexpressed Smad7, even when the cells were stimulated with recombinant TGF-β1 or ectopically expressed a constitutively active TGF-β receptor type I. Additionally, NAC dose-dependently decreased expression of three major indicators of impaired fibrotic matrix turnover, namely alpha-smooth muscle actin (α-SMA), α 1 type I procollagen (CollA1), and plasminogen activator inhibitor-type I (PAI-1). Our results suggest that TGF-β signalling and subsequent expression of fibrogenesis related proteins in Dupuytren's disease is abrogated by NAC thus providing a basis for a therapeutic strategy in Dupuytren's disease and other fibroproliferative disorders. PMID:16563228

  8. Fluorescent sensor for selective determination of copper ion based on N-acetyl-L-cysteine capped CdHgSe quantum dots.

    PubMed

    Wang, Qingqing; Yu, Xiangyang; Zhan, Guoqing; Li, Chunya

    2014-04-15

    Using N-acetyl-L-cysteine as a stabilizer, well water-dispersed, high-quality and stable CdHgSe quantum dots were facilely synthesized via a simple aqueous phase method. The as-prepared N-acetyl-L-cysteine capped CdHgSe quantum dots were thoroughly characterized by transmission electron microscopy, X-ray diffraction spectroscopy and FTIR. A fluorescent sensor for selective determination of copper ions was developed using N-acetyl-L-cysteine capped CdHgSe quantum dots as fluorescent probe. The fluorescence intensity of N-acetyl-L-cysteine capped CdHgSe quantum dots decreased when interacted with copper ions due to the formation of coordination complex and aggregates. The method possesses high selectivity and is not influenced by some potential interferences such as Ag(+), Zn(2+), Co(2+) and Ni(2+). Under the optimal conditions, the change of fluorescence intensity (ΔI) was linearly proportional to the concentration of copper ions in the range of 1.0×10(-9)-4.0×10(-7) mol L(-1), with a detection limit as low as 2.0×10(-10) mol L(-1) (S/N=3). The developed method had been successfully employed to determine Cu(2+) in shrimp and South-lake water samples, and the results were verified by atomic absorption spectroscopy. The fluorescent sensor was demonstrated to be selective, sensitive and simple for copper ion determination, and promise for practical applications. PMID:24291268

  9. N-Acetyl-Cysteine as Effective and Safe Chelating Agent in Metal-on-Metal Hip-Implanted Patients: Two Cases

    PubMed Central

    Lonati, Davide; Ragghianti, Benedetta; Ronchi, Anna; Vecchio, Sarah; Locatelli, Carlo Alessandro

    2016-01-01

    Systemic toxicity associated with cobalt (Co) and chromium (Cr) containing metal hip alloy may result in neuropathy, cardiomyopathy, and hypothyroidism. However clinical management concerning chelating therapy is still debated in literature. Here are described two metal-on-metal hip-implanted patients in which N-acetyl-cysteine decreased elevated blood metal levels. A 67-year-old male who underwent Co/Cr hip implant in September 2009 referred to our Poison Control Centre for persisting elevated Co/Cr blood levels (from March 2012 to November 2014). After receiving oral high-dose N-acetyl-cysteine, Co/Cr blood concentrations dropped by 86% and 87% of the prechelation levels, respectively, and persisted at these latter concentrations during the following 6 months of follow-up. An 81-year-old female who underwent Co/Cr hip implant in January 2007 referred to our Centre for detection of high Co and Cr blood levels in June 2012. No hip revision was indicated. After a therapy with oral high-dose N-acetyl-cysteine Co/Cr blood concentrations decreased of 45% and 24% of the prechelation levels. Chelating agents reported in hip-implanted patients (EDTA, DMPS, and BAL) are described in few cases. N-acetyl-cysteine may provide chelating sites for metals and in our cases reduced Co and Cr blood levels and resulted well tolerable. PMID:27148463

  10. Formation of the thioester, N-acetyl, S-lactoylcysteine, by reaction of N-acetylcysteine with pyruvaldehyde in aqueous solution. [in prebiotic evolution

    NASA Technical Reports Server (NTRS)

    Weber, A. L.

    1982-01-01

    N-acetylcysteine reacts efficiently with pyruvaldehyde (methylglyoxal) in aqueous solution (pH 7.0) in the presence of a weak base, like imidazole or phosphate, to give the thioester, N-acetyl, S-lactoylcysteine. Reactions of 100 mM N-acetylcysteine with 14 mM, 24 mM and 41 mM pyruvaldehyde yield, respectively, 86%, 76% and 59% N-acetyl, S-lactoylcysteine based on pyruvaldehyde. The decrease in the percent yield at higher pyruvaldehyde concentrations suggests that during its formation the thioester is not only consumed by hydrolysis, but also by reaction with some substance in the pyruvaldehyde preparation. Indeed, purified N-acetyl, S-lactoylcysteine disappears much more rapidly in the presence of pyruvaldehyde than in its absence. Presumably, N-acetyl, S-lactoylcysteine synthesis occurs by rearrangement of the hemithioacetal of N-acetylcysteine and pyruvaldehyde. The significance of this pathway of thioester formation to molecular evolution is discussed.

  11. Evaluation of in vitro toxicity of peptide (N-acetyl-Leu-Gly-Leu-COOH)-substituted-β-cyclodextrin derivative, a novel drug carrier, in PC-12 cells

    PubMed Central

    2013-01-01

    Background Cyclodextrins (CDs) have been shown to improve physicochemical and biopharmaceutical properties of drugs when low solubility and low safety limit their use in the pharmaceutical field. Recently, a new amphiphilic peptide-substituted-β-CD, hepta-(N-acetyl-Leu-Gly-Leu)-β-CD (hepta-(N-acetyl-LGL)-β-CD), is developed which exhibited good solubility, strong inclusion ability and an appropriate average molecular weight. However, there is limited information available about its toxic effects. This study was designed to evaluate cytotoxic effects of the hepta-(N-acetyl-LGL)-β-CD (50, 200, 400, and 800 μg/ml) on rat pheochromocytoma PC-12 cells. Results A significant reduction of cell viability with IC50 values of 1115.0 μg/ml, 762.4 μg/ml, and 464.9 μg/ml at 6, 12, and 24 h post-treatment, respectively, as well as increased lipid peroxide levels and DNA damage were observed. Conclusions In conclusion, hepta-(N-acetyl-Leu-Gly-Leu)-β-CD exhibit significant toxic properties at high concentrations, probably through induction of oxidative stress and genotoxicity. PMID:24359794

  12. The α-Glycosidation of Partially Unprotected N-Acetyl and N-Glycolyl Sialyl Donors in the Absence of a Nitrile Solvent Effect.

    PubMed

    Aoyagi, Taku; Ohira, Shuichi; Fuse, Shinichiro; Uzawa, Jun; Yamaguchi, Yoshiki; Tanaka, Hiroshi

    2016-05-10

    The synthesis of α-sialosides is one of the most difficult reactions in carbohydrate chemistry and is considered to be both a thermodynamically and kinetically disfavored process. The use of acetonitrile as a solvent is an effective solution for the α-selective glycosidation of N-acetyl sialic acids. In this report, we report on the α-glycosidation of partially unprotected N-acetyl and N-glycolyl donors in the absence of a nitrile solvent effect. The 9-O-benzyl-N-acetylthiosialoside underwent glycosidation in CH2 Cl2 with a good α-selectivity. On the other hand, the 4,7,8-O-triacetyl-9-O-benzyl-N-acetylthiosialoside was converted to β-sialoside as a major product under the same reaction conditions. The results indicate that the O-acetyl protection of the sialyl donor was a major factor in reducing the α-selectivity of sialylation. After tuning of the protecting groups of the hydroxy groups at the 4,7,8 position on the sialyl donor, we found that the 9-O-benzyl-4-O-chloroacetyl-N-acetylthiosialoside underwent sialylation with excellent α-selectivity in CH2 Cl2 . To demonstrate the utility of the method, straightforward synthesis of α(2,9) disialosides containing N-acetyl and/or N-glycolyl groups was achieved by using the two N-acetyl and N-glycolyl sialyl donors. PMID:27060996

  13. The alpha-N-acetyl-glucosaminidase gene is transcriptionally activated in male and female gametes prior to fertilization and is essential for seed development in Arabidopsis.

    PubMed

    Ronceret, Arnaud; Gadea-Vacas, Jose; Guilleminot, Jocelyne; Devic, Martine

    2008-01-01

    Sugar residues in proteoglycan complexes carry important signalling and regulatory functions in biology. In humans, heparan sulphate is an example of such a complex polymer containing glucosamine and N-acetyl-glucosamine residues and is present in the extracellular matrix. Although heparan sulphate has not been found in plants, the At5g13690 gene encoding the alpha-N-acetyl-glucosaminidase (NAGLU), an enzyme involved in its catabolism, is present in the Arabidopsis genome. Among our collection of embryo-defective lines, a plant was identified in which the T-DNA had inserted into the AtNAGLU gene. The phenotype of atnaglu is an early arrest of seed development without apparent male or female gametophytic effects. These data demonstrated the essential function in Arabidopsis consistent with the contribution of NAGLU to the Sanfilippo syndrome in human. Expression of AtNAGLU in plants was shown to be prevalent during reproductive development. The presence of AtNAGLU mRNA was observed during early and late male gametogenesis and in each cell of the embryo sac at the time of fertilization. After fertilization, AtNAGLU was expressed in the embryo, suspensor, and endosperm until the cotyledonary stage embryo. This precise pattern of expression identifies the cells and tissues where a remodelling of the N-acetyl-glucosamine residues of proteoglycan complexes is occurring. This work provides original evidence of the important role of N-acetyl-glucosamines in plant reproductive development. PMID:18782908

  14. sup. alpha. N-acetyl derivatives of. beta. -endorphin-(1-31) and -(1-27) regulate the supraspinal antinociceptive activity of different opioids in mice

    SciTech Connect

    Garzon, J.; Sanchez-Blazquez, P. )

    1991-01-01

    {sup {alpha}}N-acetyl human {beta}-endorphin(1-31) injected icv to mice antagonized the analgesic activity of {beta}-endorphin-(1-31) and morphine whereas the analgesia evoked by DADLE and DAGO was enhanced by this treatment. The modulatory activity of {sup {alpha}}N-acetyl {beta}-endorphin-(1-31) was exhibited at remarkable low doses (fmols) reaching a maximum that persisted even though the dose was increased 100,000 times. The regulatory effect of a single dose of the acetylated neuropeptide lasted for 24h. The activity of {sup {alpha}}N-acetyl human {beta}-endorphin(1-31) was partially retained by the shorter peptide {sup {alpha}}N-acetyl human {beta}-endorphin-(1-27) and to a lesser extent by {beta}-endorphin-(1-27), {beta}-endorphin-(1-31) lacked this regulatory activity on opioid analgesia. Acetylated {beta}-endorphin-(1-31) displayed a biphasic curve when competing with 5 pM ({sup 125}I)-Tyr{sup 27} human {beta}-endorphin-(1-31) specific binding, the first step was abolished with an apparent IC{sub 50} of 0.35 nM, and the rest with an IC{sub 50} of 200 nM. It is suggested that {sup {alpha}}N-acetyl {beta}-endorphin-(1-31) changed the efficiency of the opioid analgesics by acting upon a specific substrate that is functionally coupled to the opioid receptor, presumably the guanine nucleotide binding regulatory proteins G{sub i}/G{sub 0}.

  15. Structural Investigation of a Novel N-Acetyl Glucosamine Binding Chi-Lectin Which Reveals Evolutionary Relationship with Class III Chitinases

    PubMed Central

    Patil, Dipak N.; Datta, Manali; Dev, Aditya; Dhindwal, Sonali; Singh, Nirpendra; Dasauni, Pushpanjali; Kundu, Suman; Sharma, Ashwani K.; Tomar, Shailly; Kumar, Pravindra

    2013-01-01

    The glycosyl hydrolase 18 (GH18) family consists of active chitinases as well as chitinase like lectins/proteins (CLPs). The CLPs share significant sequence and structural similarities with active chitinases, however, do not display chitinase activity. Some of these proteins are reported to have specific functions and carbohydrate binding property. In the present study, we report a novel chitinase like lectin (TCLL) from Tamarindus indica. The crystal structures of native TCLL and its complex with N-acetyl glucosamine were determined. Similar to the other CLPs of the GH18 members, TCLL lacks chitinase activity due to mutations of key active site residues. Comparison of TCLL with chitinases and other chitin binding CLPs shows that TCLL has substitution of some chitin binding site residues and more open binding cleft due to major differences in the loop region. Interestingly, the biochemical studies suggest that TCLL is an N-acetyl glucosamine specific chi-lectin, which is further confirmed by the complex structure of TCLL with N-acetyl glucosamine complex. TCLL has two distinct N-acetyl glucosamine binding sites S1 and S2 that contain similar polar residues, although interaction pattern with N-acetyl glucosamine varies extensively among them. Moreover, TCLL structure depicts that how plants utilize existing structural scaffolds ingenuously to attain new functions. To date, this is the first structural investigation of a chi-lectin from plants that explore novel carbohydrate binding sites other than chitin binding groove observed in GH18 family members. Consequently, TCLL structure confers evidence for evolutionary link of lectins with chitinases. PMID:23717482

  16. In Vitro Biosynthesis and Chemical Identification of UDP-N-acetyl-d-quinovosamine (UDP-d-QuiNAc)*

    PubMed Central

    Li, Tiezheng; Simonds, Laurie; Kovrigin, Evgenii L.; Noel, K. Dale

    2014-01-01

    N-acetyl-d-quinovosamine (2-acetamido-2,6-dideoxy-d-glucose, QuiNAc) occurs in the polysaccharide structures of many Gram-negative bacteria. In the biosynthesis of QuiNAc-containing polysaccharides, UDP-QuiNAc is the hypothetical donor of the QuiNAc residue. Biosynthesis of UDP-QuiNAc has been proposed to occur by 4,6-dehydration of UDP-N-acetyl-d-glucosamine (UDP-GlcNAc) to UDP-2-acetamido-2,6-dideoxy-d-xylo-4-hexulose followed by reduction of this 4-keto intermediate to UDP-QuiNAc. Several specific dehydratases are known to catalyze the first proposed step. A specific reductase for the last step has not been demonstrated in vitro, but previous mutant analysis suggested that Rhizobium etli gene wreQ might encode this reductase. Therefore, this gene was cloned and expressed in Escherichia coli, and the resulting His6-tagged WreQ protein was purified. It was tested for 4-reductase activity by adding it and NAD(P)H to reaction mixtures in which 4,6-dehydratase WbpM had acted on the precursor substrate UDP-GlcNAc. Thin layer chromatography of the nucleotide sugars in the mixture at various stages of the reaction showed that WbpM converted UDP-GlcNAc completely to what was shown to be its 4-keto-6-deoxy derivative by NMR and that addition of WreQ and NADH led to formation of a third compound. Combined gas chromatography-mass spectrometry analysis of acid hydrolysates of the final reaction mixture showed that a quinovosamine moiety had been synthesized after WreQ addition. The two-step reaction progress also was monitored in real time by NMR. The final UDP-sugar product after WreQ addition was purified and determined to be UDP-d-QuiNAc by one-dimensional and two-dimensional NMR experiments. These results confirmed that WreQ has UDP-2-acetamido-2,6-dideoxy-d-xylo-4-hexulose 4-reductase activity, completing a pathway for UDP-d-QuiNAc synthesis in vitro. PMID:24817117

  17. Mechanism of allosteric inhibition of N-acetyl-L-glutamate synthase by L-arginine.

    PubMed

    Min, Li; Jin, Zhongmin; Caldovic, Ljubica; Morizono, Hiroki; Allewell, Norma M; Tuchman, Mendel; Shi, Dashuang

    2009-02-20

    N-Acetylglutamate synthase (NAGS) catalyzes the first committed step in l-arginine biosynthesis in plants and micro-organisms and is subject to feedback inhibition by l-arginine. This study compares the crystal structures of NAGS from Neisseria gonorrhoeae (ngNAGS) in the inactive T-state with l-arginine bound and in the active R-state complexed with CoA and l-glutamate. Under all of the conditions examined, the enzyme consists of two stacked trimers. Each monomer has two domains: an amino acid kinase (AAK) domain with an AAK-like fold but lacking kinase activity and an N-acetyltransferase (NAT) domain homologous to other GCN5-related transferases. Binding of l-arginine to the AAK domain induces a global conformational change that increases the diameter of the hexamer by approximately 10 A and decreases its height by approximately 20A(.) AAK dimers move 5A outward along their 2-fold axes, and their tilt relative to the plane of the hexamer decreases by approximately 4 degrees . The NAT domains rotate approximately 109 degrees relative to AAK domains enabling new interdomain interactions. Interactions between AAK and NAT domains on different subunits also change. Local motions of several loops at the l-arginine-binding site enable the protein to close around the bound ligand, whereas several loops at the NAT active site become disordered, markedly reducing enzymatic specific activity. PMID:19095660

  18. Mechanism of Allosteric Inhibition of N-Acetyl-L-glutamate Synthase by L-Arginine*

    PubMed Central

    Min, Li; Jin, Zhongmin; Caldovic, Ljubica; Morizono, Hiroki; Allewell, Norma M.; Tuchman, Mendel; Shi, Dashuang

    2009-01-01

    N-Acetylglutamate synthase (NAGS) catalyzes the first committed step in l-arginine biosynthesis in plants and micro-organisms and is subject to feedback inhibition by l-arginine. This study compares the crystal structures of NAGS from Neisseria gonorrhoeae (ngNAGS) in the inactive T-state with l-arginine bound and in the active R-state complexed with CoA and l-glutamate. Under all of the conditions examined, the enzyme consists of two stacked trimers. Each monomer has two domains: an amino acid kinase (AAK) domain with an AAK-like fold but lacking kinase activity and an N-acetyltransferase (NAT) domain homologous to other GCN5-related transferases. Binding of l-arginine to the AAK domain induces a global conformational change that increases the diameter of the hexamer by ∼10 Å and decreases its height by ∼20Å. AAK dimers move 5Å outward along their 2-fold axes, and their tilt relative to the plane of the hexamer decreases by ∼4°. The NAT domains rotate ∼109° relative to AAK domains enabling new interdomain interactions. Interactions between AAK and NAT domains on different subunits also change. Local motions of several loops at the l-arginine-binding site enable the protein to close around the bound ligand, whereas several loops at the NAT active site become disordered, markedly reducing enzymatic specific activity. PMID:19095660

  19. Mechanism of Allosteric Inhibition of N-Acetyl-L-glutamate Synthase by L-Arginine

    SciTech Connect

    Min, Li; Jin, Zhongmin; Caldovic, Ljubica; Morizono, Hiroki; Allewell, Norma M.; Tuchman, Mendel; Shi, Dashuang

    2010-01-07

    N-Acetylglutamate synthase (NAGS) catalyzes the first committed step in L-arginine biosynthesis in plants and micro-organisms and is subject to feedback inhibition by L-arginine. This study compares the crystal structures of NAGS from Neisseria gonorrhoeae (ngNAGS) in the inactive T-state with L-arginine bound and in the active R-state complexed with CoA and L-glutamate. Under all of the conditions examined, the enzyme consists of two stacked trimers. Each monomer has two domains: an amino acid kinase (AAK) domain with an AAK-like fold but lacking kinase activity and an N-acetyltransferase (NAT) domain homologous to other GCN5-related transferases. Binding of L-arginine to the AAK domain induces a global conformational change that increases the diameter of the hexamer by {approx}10 {angstrom} and decreases its height by {approx}20{angstrom}. AAK dimers move 5{angstrom} outward along their 2-fold axes, and their tilt relative to the plane of the hexamer decreases by {approx}4{sup o}. The NAT domains rotate {approx}109{sup o} relative to AAK domains enabling new interdomain interactions. Interactions between AAK and NAT domains on different subunits also change. Local motions of several loops at the L-arginine-binding site enable the protein to close around the bound ligand, whereas several loops at the NAT active site become disordered, markedly reducing enzymatic specific activity.

  20. Understanding N-Acetyl-L-Glutamate Synthase Deficiency: Mutational Spectrum, Impact of Clinical Mutations on Enzyme Functionality, and Structural Considerations.

    PubMed

    Sancho-Vaello, Enea; Marco-Marín, Clara; Gougeard, Nadine; Fernández-Murga, Leonor; Rüfenacht, Véronique; Mustedanagic, Merima; Rubio, Vicente; Häberle, Johannes

    2016-07-01

    N-acetyl-L-glutamate synthase (NAGS) deficiency (NAGSD), the rarest urea cycle defect, is clinically indistinguishable from carbamoyl phosphate synthetase 1 deficiency, rendering the identification of NAGS gene mutations key for differentiation, which is crucial, as only NAGSD has substitutive therapy. Over the last 13 years, we have identified 43 patients from 33 families with NAGS mutations, of which 14 were novel. Overall, 36 NAGS mutations have been found so far in 56 patients from 42 families, of which 76% are homozygous for the mutant allele. 61% of mutations are missense changes. Lack or decrease of NAGS protein is predicted for ∼1/3 of mutations. Missense mutations frequency is inhomogeneous along NAGS: null for exon 1, but six in exon 6, which reflects the paramount substrate binding/catalytic role of the C-terminal domain (GNAT domain). Correspondingly, phenotypes associated with missense mutations mapping in the GNAT domain are more severe than phenotypes of amino acid kinase domain-mapping missense mutations. Enzyme activity and stability assays with 12 mutations introduced into pure recombinant Pseudomonas aeruginosa NAGS, together with in silico structural analysis, support the pathogenic role of most NAGSD-associated mutations found. The disease-causing mechanisms appear to be, from higher to lower frequency, decreased solubility/stability, aberrant kinetics/catalysis, and altered arginine modulation. PMID:27037498

  1. Protective effects of Eugenia jambolana extract versus N-acetyl cysteine against cisplatin-induced damage in rat testis.

    PubMed

    Anand, H; Misro, M M; Sharma, S B; Prakash, S

    2015-03-01

    To assess the protective effects of Eugenia jambolana extract (EJE) or N-acetyl cysteine (NAC) on testis, cisplatin (CIS, 5 mg kg(-1) bw, single dose) was administered either alone or along with EJE (25 mg kg(-1) bw, alternate day) or NAC (150 mg kg(-1) bw, Day 1 and 4) for 7 days. Significant alterations in serum LH, FSH and testosterone were observed in CIS group which were effectively modulated by EJE or NAC supplementation. Upregulation of 3β-HSD gene indicated the rise in functional Leydig cells. This was further confirmed from the identical improvement in hCG-stimulated testosterone production in isolated Leydig cells. Reduction in oxidative stress was associated with restoration of total antioxidant capacity and glutathione levels, and activation of antioxidant enzymes, SOD, catalase, glutathione s-transferase (GST) and glutathione reductase (GR). CIS-induced apoptosis of germ and Leydig cells was contained by both NAC and EJE intervention by effective modulation of apoptotic markers in the extrinsic, intrinsic and other pathways of metazoan apoptosis. Taken together, the study findings establish the potential of EJE as a therapeutically better antioxidant than NAC for use in curtailing the adverse effects of anticancer drugs on testicular function. PMID:24576220

  2. Scope and Limitations of 3-Iodo-Kdo Fluoride-Based Glycosylation Chemistry using N-Acetyl Glucosamine Acceptors.

    PubMed

    Pokorny, Barbara; Kosma, Paul

    2015-12-01

    The ketosidic linkage of 3-deoxy-d-manno-octulosonic acid (Kdo) to lipid A constitutes a general structural feature of the bacterial lipopolysaccharide core. Glycosylation reactions of Kdo donors, however, are challenging due to the absence of a directing group at C-3 and elimination reactions resulting in low yields and anomeric selectivities of the glycosides. While 3-iodo-Kdo fluoride donors showed excellent glycosyl donor properties for the assembly of Kdo oligomers, glycosylation of N-acetyl-glucosamine derivatives was not straightforward. Specifically, oxazoline formation of a β-anomeric methyl glycoside, as well as iodonium ion transfer to an allylic aglycon was found. In addition, dehalogenation of the directing group by hydrogen atom transfer proved to be incompatible with free hydroxyl groups next to benzyl groups. In contrast, glycosylation of a suitably protected methyl 2-acetamido-2-deoxy-α-d-glucopyranoside derivative and subsequent deiodination proceeded in excellent yields and α-specificity, and allowed for subsequent 4-O-phosphorylation. This way, the disaccharides α-Kdo-(2→6)-α-GlcNAcOMe and α-Kdo-(2→6)-α-GlcNAcOMe-4-phosphate were obtained in good overall yields. PMID:27308198

  3. Spectroscopic investigations on the effect of N-Acetyl-L-cysteine-Capped CdTe Quantum Dots on catalase

    NASA Astrophysics Data System (ADS)

    Sun, Haoyu; Yang, Bingjun; Cui, Erqian; Liu, Rutao

    2014-11-01

    Quantum dots (QDs) are recognized as some of the most promising semiconductor nanocrystals in biomedical applications. However, the potential toxicity of QDs has aroused wide public concern. Catalase (CAT) is a common enzyme in animal and plant tissues. For the potential application of QDs in vivo, it is important to investigate the interaction of QDs with CAT. In this work, the effect of N-Acetyl-L-cysteine-Capped CdTe Quantum Dots with fluorescence emission peak at 612 nm (QDs-612) on CAT was investigated by fluorescence, synchronous fluorescence, fluorescence lifetime, ultraviolet-visible (UV-vis) absorption and circular dichroism (CD) techniques. Binding of QDs-612 to CAT caused static quenching of the fluorescence, the change of the secondary structure of CAT and the alteration of the microenvironment of tryptophan residues. The association constants K were determined to be K288K = 7.98 × 105 L mol-1 and K298K = 7.21 × 105 L mol-1. The interaction between QDs-612 and CAT was spontaneous with 1:1 stoichiometry approximately. The CAT activity was also inhibited for the bound QDs-612. This work provides direct evidence about enzyme toxicity of QDs-612 to CAT in vitro and establishes a new strategy to investigate the interaction between enzyme and QDs at a molecular level, which is helpful for clarifying the bioactivities of QDs in vivo.

  4. A 4-deoxy analogue of N-acetyl-D-glucosamine inhibits heparan sulphate expression and growth factor binding in vitro

    SciTech Connect

    Wijk, Xander M.R. van; Oosterhof, Arie; Broek, Sebastiaan A.M.W. van den; Griffioen, Arjan W.; Dam, Gerdy B. ten; Rutjes, Floris P.J.T.; Delft, Floris L. van; Kuppevelt, Toin H. van

    2010-09-10

    Heparan sulphate (HS) is a long, linear polysaccharide, which has a basic backbone of -{beta}1-4GlcA-{alpha}1-4GlcNAc- units. The involvement of HS in many steps of tumourigenesis, including growth and angiogenesis, makes it an appealing target for cancer therapy. To target the biosynthesis of HS by interfering with its chain elongation, a 4-deoxy analogue of N-acetyl-D-glucosamine (4-deoxy-GlcNAc) was synthesized. Using immunocytochemistry and agarose gel electrophoresis it was shown that incubation with the 4-deoxysugar resulted in a dose dependent reduction of HS expression of MV3 melanoma cells, 1 mM resulting in an almost nullified HS expression. The parent sugar GlcNAc had no effect. 4-deoxysugar treated cells were viable and proliferated at the same rate as control cells. Other glycan structures appeared to be only mildly affected, as staining by various lectins was generally not or only modestly inhibited. At 1 mM of the 4-deoxysugar, the capacity of cells to bind the HS-dependent pro-angiogenic growth factors FGF-2 and VEGF was greatly compromised. Using an in vitro angiogenesis assay, 4-deoxysugar treated endothelial cells showed a sharp reduction of FGF-2-induced sprout formation. Combined, these data indicate that an inexpensive, easily synthesized, water-soluble monosaccharide analogue can interfere with HS expression and pro-angiogenic growth factor binding.

  5. Interactions between the nitrogen signal transduction protein PII and N-acetyl glutamate kinase in organisms that perform oxygenic photosynthesis.

    PubMed

    Burillo, Sergio; Luque, Ignacio; Fuentes, Inmaculada; Contreras, Asunción

    2004-06-01

    PII, one of the most conserved signal transduction proteins, is believed to be a key player in the coordination of nitrogen assimilation and carbon metabolism in bacteria, archaea, and plants. However, the identity of PII receptors remains elusive, particularly in photosynthetic organisms. Here we used yeast two-hybrid approaches to identify new PII receptors and to explore the extent of conservation of PII signaling mechanisms between eubacteria and photosynthetic eukaryotes. Screening of Synechococcus sp. strain PCC 7942 libraries with PII as bait resulted in identification of N-acetyl glutamate kinase (NAGK), a key enzyme in the biosynthesis of arginine. The integrity of Ser49, a residue conserved in PII proteins from organisms that perform oxygenic photosynthesis, appears to be essential for NAGK binding. The effect of glnB mutations on NAGK activity is consistent with positive regulation of NAGK by PII. Phylogenetic and yeast two-hybrid analyses strongly suggest that there was conservation of the NAGK-PII regulatory interaction in the evolution of cyanobacteria and chloroplasts, providing insight into the function of eukaryotic PII-like proteins. PMID:15150219

  6. Mutational analysis to identify the residues essential for the inhibition of N-acetyl glutamate kinase of Corynebacterium glutamicum.

    PubMed

    Huang, Yuanyuan; Zhang, Hao; Tian, Hongming; Li, Cheng; Han, Shuangyan; Lin, Ying; Zheng, Suiping

    2015-09-01

    N-acetyl glutamate kinase (NAGK) is a key enzyme in the synthesis of L-arginine that is inhibited by its end product L-arginine in Corynebacterium glutamicum (C. glutamicum). In this study, the potential binding sites of arginine and the residues essential for its inhibition were identified by homology modeling, inhibitor docking, and site-directed mutagenesis. The allosteric inhibition of NAGK was successfully alleviated by a mutation, as determined through analysis of mutant enzymes, which were overexpressed in vivo in C. glutamicum ATCC14067. Analysis of the mutant enzymes and docking analysis demonstrated that residue W23 positions an arginine molecule, and the interaction between arginine and residues L282, L283, and T284 may play an important role in the remote inhibitory process. Based on the results of the docking analysis of the effective mutants, we propose a linkage mechanism for the remote allosteric regulation of NAGK activity, in which residue R209 may play an essential role. In this study, the structure of the arginine-binding site of C. glutamicum NAGK (CgNAGK) was successfully predicted and the roles of the relevant residues were identified, providing new insight into the allosteric regulation of CgNAGK activity and a solid platform for the future construction of an optimized L-arginine producing strain. PMID:25750030

  7. Identification of the enzyme responsible for N-acetylation of norfloxacin by Microbacterium sp. Strain 4N2-2.

    PubMed

    Kim, Dae-Wi; Feng, Jinhui; Chen, Huizhong; Kweon, Ohgew; Gao, Yuan; Yu, Li-Rong; Burrowes, Vanessa J; Sutherland, John B

    2013-01-01

    Microbacterium sp. 4N2-2, isolated from a wastewater treatment plant, converts the antibacterial fluoroquinolone norfloxacin to N-acetylnorfloxacin and three other metabolites. Because N-acetylation results in loss of antibacterial activity, identification of the enzyme responsible is important for understanding fluoroquinolone resistance. The enzyme was identified as glutamine synthetase (GS); N-acetylnorfloxacin was produced only under conditions associated with GS expression. The GS gene (glnA) was cloned, and the protein (53 kDa) was heterologously expressed and isolated. Optimal conditions and biochemical properties (K(m) and V(max)) of purified GS were characterized; the purified enzyme was inhibited by Mn(2+), Mg(2+), ATP, and ADP. The contribution of GS to norfloxacin resistance was shown by using a norfloxacin-sensitive Escherichia coli strain carrying glnA derived from Microbacterium sp. 4N2-2. The GS of Microbacterium sp. 4N2-2 was shown to act as an N-acetyltransferase for norfloxacin, which produced low-level norfloxacin resistance. Structural and docking analysis identified potential binding sites for norfloxacin at the ADP binding site and for acetyl coenzyme A (acetyl-CoA) at a cleft in GS. The results suggest that environmental bacteria whose enzymes modify fluoroquinolones may be able to survive in the presence of low fluoroquinolone concentrations. PMID:23104417

  8. Urinary N-acetyl-beta-D-glucosaminidase and malondialdehyde as a markers of renal damage in burned patients.

    PubMed Central

    Kang, H. K.; Kim, D. K.; Lee, B. H.; Om, A. S.; Hong, J. H.; Koh, H. C.; Lee, C. H.; Shin, I. C.; Kang, J. S.

    2001-01-01

    This study was aimed to evaluate renal dysfunction during three weeks after the burn injuries in 12 patients admitted to the Hallym University Hankang Medical Center with flame burn injuries (total body surface area, 20-40%). Parameters assessed included 24-hr urine volume, blood urea nitrogen, serum creatinine, creatinine clearance, total urinary protein, urinary microalbumin, 24-hr urinary N-acetyl-beta-D-glucosaminidase (NAG) activity, and urinary malondialdehyde (MDA). Statistical analysis was performed using repeated measures ANOVA test. The 24-hr urine volume, creatinine clearance, and urinary protein significantly increased on day 3 post-burn and fell thereafter. The urine microalbumin excretion showed two peak levels on day 0 post-burn and day 3. The 24-hr urinary NAG activity significantly increased to its maximal level on day 7 post-burn and gradually fell thereafter. The urinary MDA progressively increased during 3 weeks after the burn injury. Despite recovery of general renal function through an intensive care of burn injury, renal tubular damage and lipid peroxidation of the renal tissue suggested to persist during three weeks after the burn. Therefore, a close monitoring and intensive management of renal dysfunction is necessary to prevent burn-induced acute renal failure as well as to lower mortality in patients with major burns. PMID:11641529

  9. N-Acetyl-Serotonin Protects HepG2 Cells from Oxidative Stress Injury Induced by Hydrogen Peroxide

    PubMed Central

    Jiang, Jiying; Yu, Shuna; Jiang, Zhengchen; Liang, Cuihong; Yu, Wenbo; Li, Jin; Du, Xiaodong; Wang, Hailiang; Gao, Xianghong; Wang, Xin

    2014-01-01

    Oxidative stress plays an important role in the pathogenesis of liver diseases. N-Acetyl-serotonin (NAS) has been reported to protect against oxidative damage, though the mechanisms by which NAS protects hepatocytes from oxidative stress remain unknown. To determine whether pretreatment with NAS could reduce hydrogen peroxide- (H2O2-) induced oxidative stress in HepG2 cells by inhibiting the mitochondrial apoptosis pathway, we investigated the H2O2-induced oxidative damage to HepG2 cells with or without NAS using MTT, Hoechst 33342, rhodamine 123, Terminal dUTP Nick End Labeling Assay (TUNEL), dihydrodichlorofluorescein (H2DCF), Annexin V and propidium iodide (PI) double staining, immunocytochemistry, and western blot. H2O2 produced dramatic injuries in HepG2 cells, represented by classical morphological changes of apoptosis, increased levels of malondialdehyde (MDA) and intracellular reactive oxygen species (ROS), decreased activity of superoxide dismutase (SOD), and increased activities of caspase-9 and caspase-3, release of cytochrome c (Cyt-C) and apoptosis-inducing factor (AIF) from mitochondria, and loss of membrane potential (ΔΨm). NAS significantly inhibited H2O2-induced changes, indicating that it protected against H2O2-induced oxidative damage by reducing MDA levels and increasing SOD activity and that it protected the HepG2 cells from apoptosis through regulating the mitochondrial apoptosis pathway, involving inhibition of mitochondrial hyperpolarization, release of mitochondrial apoptogenic factors, and caspase activity. PMID:25013541

  10. Comparison of N-acetyl-beta-D-glucosaminidase and alanine aminopeptidase activities for evaluation of microangiopathy in diabetes mellitus.

    PubMed

    Shimojo, N; Kitahashi, S; Naka, K; Fujii, A; Okuda, K; Tanaka, S; Fujii, S

    1987-03-01

    The activities of urinary N-acetyl-beta-D-glucosaminidase (NAG) and alanine aminopeptidase (AAP) were measured in 207 diabetic patients and 57 healthy controls, and the relationship of these enzymes to different stages of diabetic microangiopathy was studied. Diabetics with clinical proteinuria had higher urinary NAG and AAP (17.7 +/- 1.9 and 42.8 +/- 4.9 U/g creatinine, mean +/- SE, respectively) than healthy controls (1.8 +/- 0.1 and 10.0 +/- 0.4) or diabetics without proteinuria. Among diabetics without proteinuria, NAG excretion in those with retinopathy was slightly higher than in those without (6.4 +/- 0.5 v 5.4 +/- 0.4), and AAP in those with retinopathy was significantly higher than in those without (23.0 +/- 1.5 v 17.4 +/- 0.8, P less than 0.01). Urinary albumin measured by radioimmunoassay and lysozyme in diabetics with retinopathy but without proteinuria was higher than those without retinopathy (P less than 0.001 and P less than 0.01). The increase in albumin was the greatest in diabetics with long duration of the disease (greater than or equal to 8 years); however, NAG and AAP increased more significantly in those with high hemoglobin A1c than in patients with long duration.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2881186

  11. N-Acetyl-Cysteine Promotes Angiostatin Production and Vascular Collapse in an Orthotopic Model of Breast Cancer

    PubMed Central

    Agarwal, Anshu; Muñoz-Nájar, Ursula; Klueh, Ulrike; Shih, Shu-Ching; Claffey, Kevin P.

    2004-01-01

    The antioxidant N-acetyl-cysteine (NAC) has been shown to be chemopreventive in clinical studies, and in recent studies, has shown promise in preventing tumor progression. Although the effects of NAC on tumorigenesis have been associated with decreased angiogenesis, the mechanism of the anti-angiogenic activity has not been determined. In the following study, we describe a novel mechanism whereby NAC therapy blocks MDA-MB-435 breast carcinoma cell proliferation and metastasis in an in vivo tumorigenic model. Athymic nude mice bearing MDA-MB-435 xenografts were treated with systemic NAC daily for 8 weeks. NAC treatment resulted in endothelial cell apoptosis and reduction of microvascular density within the core of the tumor leading to significant tumor cell apoptosis/necrosis. Angiostatin accumulated in tumors from NAC-treated but not control animals. Additional studies using a vascular endothelial growth factor-dependent chicken chorioallantoic membrane angiogenic assay recapitulated NAC-induced endothelial apoptosis and coordinate production of angiostatin, a potent endothelial apoptotic factor. In vitro studies showed angiostatin was formed in endothelial cultures in a vascular endothelial growth factor- and NAC-dependent manner, a process that requires endothelial cell surface plasminogen activation. These results suggest that systemic NAC therapy promotes anti-angiogenesis through angiostatin production, resulting in endothelial apoptosis and vascular collapse in the tumor. PMID:15111315

  12. N-acetyl-L-cysteine affects growth, extracellular polysaccharide production, and bacterial biofilm formation on solid surfaces.

    PubMed

    Olofsson, Ann-Cathrin; Hermansson, Malte; Elwing, Hans

    2003-08-01

    N-Acetyl-L-cysteine (NAC) is used in medical treatment of patients with chronic bronchitis. The positive effects of NAC treatment have primarily been attributed to the mucus-dissolving properties of NAC, as well as its ability to decrease biofilm formation, which reduces bacterial infections. Our results suggest that NAC also may be an interesting candidate for use as an agent to reduce and prevent biofilm formation on stainless steel surfaces in environments typical of paper mill plants. Using 10 different bacterial strains isolated from a paper mill, we found that the mode of action of NAC is chemical, as well as biological, in the case of bacterial adhesion to stainless steel surfaces. The initial adhesion of bacteria is dependent on the wettability of the substratum. NAC was shown to bind to stainless steel, increasing the wettability of the surface. Moreover, NAC decreased bacterial adhesion and even detached bacteria that were adhering to stainless steel surfaces. Growth of various bacteria, as monocultures or in a multispecies community, was inhibited at different concentrations of NAC. We also found that there was no detectable degradation of extracellular polysaccharides (EPS) by NAC, indicating that NAC reduced the production of EPS, in most bacteria tested, even at concentrations at which growth was not affected. Altogether, the presence of NAC changes the texture of the biofilm formed and makes NAC an interesting candidate for use as a general inhibitor of formation of bacterial biofilms on stainless steel surfaces. PMID:12902275

  13. Spectroscopic investigations on the effect of N-acetyl-L-cysteine-capped CdTe Quantum Dots on catalase.

    PubMed

    Sun, Haoyu; Yang, Bingjun; Cui, Erqian; Liu, Rutao

    2014-11-11

    Quantum dots (QDs) are recognized as some of the most promising semiconductor nanocrystals in biomedical applications. However, the potential toxicity of QDs has aroused wide public concern. Catalase (CAT) is a common enzyme in animal and plant tissues. For the potential application of QDs in vivo, it is important to investigate the interaction of QDs with CAT. In this work, the effect of N-Acetyl-L-cysteine-Capped CdTe Quantum Dots with fluorescence emission peak at 612 nm (QDs-612) on CAT was investigated by fluorescence, synchronous fluorescence, fluorescence lifetime, ultraviolet-visible (UV-vis) absorption and circular dichroism (CD) techniques. Binding of QDs-612 to CAT caused static quenching of the fluorescence, the change of the secondary structure of CAT and the alteration of the microenvironment of tryptophan residues. The association constants K were determined to be K288K=7.98×10(5)Lmol(-1) and K298K=7.21×10(5)Lmol(-1). The interaction between QDs-612 and CAT was spontaneous with 1:1 stoichiometry approximately. The CAT activity was also inhibited for the bound QDs-612. This work provides direct evidence about enzyme toxicity of QDs-612 to CAT in vitro and establishes a new strategy to investigate the interaction between enzyme and QDs at a molecular level, which is helpful for clarifying the bioactivities of QDs in vivo. PMID:24910977

  14. Community shifts of actively growing lake bacteria after N-acetyl-glucosamine addition: improving the BrdU-FACS method.

    PubMed

    Tada, Yuya; Grossart, Hans-Peter

    2014-02-01

    In aquatic environments, community dynamics of bacteria, especially actively growing bacteria (AGB), are tightly linked with dissolved organic matter (DOM) quantity and quality. We analyzed the community dynamics of DNA-synthesizing and accordingly AGB by linking an improved bromodeoxyuridine immunocytochemistry approach with fluorescence-activated cell sorting (BrdU-FACS). FACS-sorted cells of even oligotrophic ecosystems in winter were characterized by 16S rRNA gene analysis. In incubation experiments, we examined community shifts of AGB in response to the addition of N-acetyl-glucosamine (NAG), one of the most abundant aminosugars in aquatic systems. Our improved BrdU-FACS analysis revealed that AGB winter communities of oligotrophic Lake Stechlin (northeastern Germany) substantially differ from those of total bacteria and consist of Alpha-, Beta-, Gamma-, Deltaproteobacteria, Actinobacteria, Candidatus OP10 and Chloroflexi. AGB populations with different BrdU-fluorescence intensities and cell sizes represented different phylotypes suggesting that single-cell growth potential varies at the taxon level. NAG incubation experiments demonstrated that a variety of widespread taxa related to Alpha-, Beta-, Gammaproteobacteria, Bacteroidetes, Actinobacteria, Firmicutes, Planctomycetes, Spirochaetes, Verrucomicrobia and Chloroflexi actively grow in the presence of NAG. The BrdU-FACS approach enables detailed phylogenetic studies of AGB and, thus, to identify those phylotypes which are potential key players in aquatic DOM cycling. PMID:23985742

  15. Community shifts of actively growing lake bacteria after N-acetyl-glucosamine addition: improving the BrdU-FACS method

    PubMed Central

    Tada, Yuya; Grossart, Hans-Peter

    2014-01-01

    In aquatic environments, community dynamics of bacteria, especially actively growing bacteria (AGB), are tightly linked with dissolved organic matter (DOM) quantity and quality. We analyzed the community dynamics of DNA-synthesizing and accordingly AGB by linking an improved bromodeoxyuridine immunocytochemistry approach with fluorescence-activated cell sorting (BrdU-FACS). FACS-sorted cells of even oligotrophic ecosystems in winter were characterized by 16S rRNA gene analysis. In incubation experiments, we examined community shifts of AGB in response to the addition of N-acetyl-glucosamine (NAG), one of the most abundant aminosugars in aquatic systems. Our improved BrdU-FACS analysis revealed that AGB winter communities of oligotrophic Lake Stechlin (northeastern Germany) substantially differ from those of total bacteria and consist of Alpha-, Beta-, Gamma-, Deltaproteobacteria, Actinobacteria, Candidatus OP10 and Chloroflexi. AGB populations with different BrdU-fluorescence intensities and cell sizes represented different phylotypes suggesting that single-cell growth potential varies at the taxon level. NAG incubation experiments demonstrated that a variety of widespread taxa related to Alpha-, Beta-, Gammaproteobacteria, Bacteroidetes, Actinobacteria, Firmicutes, Planctomycetes, Spirochaetes, Verrucomicrobia and Chloroflexi actively grow in the presence of NAG. The BrdU-FACS approach enables detailed phylogenetic studies of AGB and, thus, to identify those phylotypes which are potential key players in aquatic DOM cycling. PMID:23985742

  16. An N-Acetyl Cysteine Ruthenium Tricarbonyl Conjugate Enables Simultaneous Release of CO and Ablation of Reactive Oxygen Species

    PubMed Central

    Seixas, João D; Chaves-Ferreira, Miguel; Montes-Grajales, Diana; Gonçalves, Ana M; Marques, Ana R; Saraiva, Lígia M; Olivero-Verbel, Jesus; Romão, Carlos C; Bernardes, Gonçalo J L

    2015-01-01

    We have designed and synthesised a [Ru(CO)3Cl2(NAC)] pro-drug that features an N-acetyl cysteine (NAC) ligand. This NAC carbon monoxide releasing molecule (CORM) conjugate is able to simultaneously release biologically active CO and to ablate the concurrent formation of reactive oxygen species (ROS). Complexes of the general formulae [Ru(CO)3(L)3]2+, including [Ru(CO)3Cl(glycinate)] (CORM-3), have been shown to produce ROS through a water–gas shift reaction, which contributes significantly, for example, to their antibacterial activity. In contrast, NAC-CORM conjugates do not produce ROS or possess antibacterial activity. In addition, we demonstrate the synergistic effect of CO and NAC both for the inhibition of nitric oxide (formation) and in the expression of tumour-necrosis factor (TNF)-α. This work highlights the advantages of combining a CO-releasing scaffold with the anti-oxidant and anti-inflammatory drug NAC in a unique pro-drug. PMID:26316066

  17. MRS reveals additional hexose N-acetyl resonances in the brain of a mouse model for Sandhoff disease.

    PubMed

    Lowe, J P; Stuckey, D J; Awan, F R; Jeyakumar, M; Neville, D C A; Platt, F M; Griffin, J L; Styles, P; Blamire, A M; Sibson, N R

    2005-12-01

    Sandhoff disease, one of several related lysosomal storage disorders, results from the build up of N-acetyl-containing glycosphingolipids in the brain and is caused by mutations in the genes encoding the hexosaminidase beta-subunit. Affected individuals undergo progressive neurodegeneration in response to the glycosphingolipid storage. (1)H magnetic resonance spectra of perchloric acid extracts of Sandhoff mouse brain exhibited several resonances ca 2.07 ppm that were not present in the corresponding spectra from extracts of wild-type mouse brain. High-performance liquid chromatography and mass spectrometry of the Sandhoff extracts post-MRS identified the presence of N-acetylhexosamine-containing oligosaccharides, which are the likely cause of the additional MRS resonances. MRS of intact brain tissue with magic angle spinning also showed additional resonances at ca 2.07 ppm in the Sandhoff case. These resonances appeared to increase with disease progression and probably arise, for the most part, from the stored glycosphingolipids, which are absent in the aqueous extracts. Hence in vivo MRS may be a useful tool for detecting early-stage Sandhoff disease and response to treatment. PMID:16206131

  18. Purification and characterization of an extracellular muramidase of Clostridium acetobutylicum ATCC 824 that acts on non-N-acetylated peptidoglycan.

    PubMed Central

    Croux, C; Canard, B; Goma, G; Soucaille, P

    1992-01-01

    An extracellular enzyme showing lytic activity on non-N-acetylated peptidoglycan has been isolated from Clostridium acetobutylicum ATCC 824. The lytic enzyme was purified to homogeneity by anion-exchange chromatography and gel filtration, with a recovery of 24%. The enzyme was monomeric and had an estimated molecular weight of 41,000 and an isoelectric point of 3.8. It has been characterized as a muramidase whose 23-amino-acid N terminus displayed 39% homology with the N,O-diacetyl muramidase of the fungus Chalaropsis sp. The muramidase hydrolyzed purified cell walls at an optimum pH of 3, with a maximum velocity of 9.1 mumol of reducing sugars released min-1 mg of muramidase-1 and a concentration of cell walls giving a half-maximum rate of 0.01 mg ml-1. Its activity was inhibited by glucosamine, N-acetylglucosamine, Hg2+, Fe3+, and Ag+ but not by choline. The muramidase-peptidoglycan complex rapidly dissociated before total hydrolysis of the chain and randomly reassociated on another peptidoglycan chain. The affinity of the muramidase was affected by the protein content and the acetylation of the cell wall. Images PMID:1599233

  19. A double-blind, placebo-controlled study of N-acetyl cysteine plus naltrexone for methamphetamine dependence.

    PubMed

    Grant, Jon E; Odlaug, Brian L; Kim, Suck Won

    2010-11-01

    Reducing both glutamatergic and dopaminergic drive in the nucleus accumbens may offer complementary mechanisms by which to reduce drug cravings. This 8-week study sought to examine the efficacy of a combination of a glutamate modulator, N-acetyl cysteine (NAC), plus the opioid antagonist, naltrexone, compared to placebo in the treatment of methamphetamine dependence. Thirty-one subjects with methamphetamine dependence (mean age 36.8 ± 7.12 years; 29% female) were randomly assigned in a 1:1 fashion to NAC plus naltrexone or placebo and returned for one post-baseline visit. The Penn Craving Scale was the primary outcome measure. Self-report methamphetamine use frequency and urine toxicology were secondary measures. NAC plus naltrexone failed to demonstrate statistically significant differences from placebo on primary and secondary outcomes. The current study failed to demonstrate greater efficacy for NAC plus naltrexone compared to placebo. Given the small sample size, the statistical power to detect significant effects of active treatment versus placebo was limited. The question of whether a larger, well-powered sample would have detected differences between NAC plus naltrexone and placebo deserves further examination. PMID:20655182

  20. Spectroscopic and molecular docking studies on the interaction between N-acetyl cysteine and bovine serum albumin.

    PubMed

    Jahanban-Esfahlan, Ali; Panahi-Azar, Vahid; Sajedi, Sanaz

    2015-11-01

    The interaction between N-acetyl cysteine (NAC) and bovine serum albumin (BSA) was investigated by UV-vis, fluorescence spectroscopy, and molecular docking methods. Fluorescence study at three different temperatures indicated that the fluorescence intensity of BSA was reduced upon the addition of NAC by the static quenching mechanism. Binding constant (K(b)) and the number of binding sites (n) were determined. The binding constant for the interaction of NAC and BSA was in the order of 10(3) M(-1), and the number of binding sites was obtained to be equal to 1. Enthalpy (ΔH), entropy (ΔS), and Gibb's free energy (ΔG) as thermodynamic values were also achieved by van't Hoff equation. Hydrogen bonding and van der Waals force were the major intermolecular forces in the interaction process and it was spontaneous. Finally, the binding mode and the binding sites were clarified using molecular docking which were in good agreement with the results of spectroscopy experiments. PMID:26139573

  1. Optimized deglycosylation of glycoproteins by peptide-N4-(N-acetyl-beta-glucosaminyl)-asparagine amidase from Flavobacterium meningosepticum.

    PubMed

    Nuck, R; Zimmermann, M; Sauvageot, D; Josi D; Reutter, W

    1990-01-01

    Peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F(PNGase F) from Flavobacterium meningosepticum is a highly useful enzyme for the structural analysis of N (asparagine)-linked carbohydrate chains derived from glycoproteins. The enzyme was enriched using a published procedure [Tarentino AL, Gomez CM, Plummer TH, Jr (1984) Biochemistry 1985:4665-71; Tarentino AL, Plummer TH, Jr (1987) Methods Enzymol 138:770-78] and further purified by hydrophobic interaction HPLC on a weak hydrophobic TSK-Ether column from which it was eluted by a decreasing gradient of 1.7 M ammonium sulphate in 100 mM sodium phosphate, pH 7.0, containing 5 mM EDTA. To determine the optimal conditions for a complete deglycosylation of glycoproteins by PNGase F, experiments were performed with human alpha 1-acid glycoprotein, because the five complex type carbohydrate chains are quite resistant to enzymic hydrolysis. The influence of different detergents on the enzyme reaction was studied. Complete deglycosylation of human alpha 1-acid glycoprotein was achieved by the use of 60 mU/ml PNGase F in 0.25 M sodium phosphate buffer, pH 8.6, containing 0.2% (w/v) SDS, 20 mM mercaptoethanol and 0.5% Mega-10. PMID:2136346

  2. Induction of apoptosis in cancer cells through N-acetyl-l-leucine-modified polyethylenimine-mediated p53 gene delivery.

    PubMed

    Li, Zhiyuan; Zhang, Liu; Li, Quanshun

    2015-11-01

    Herein, N-acetyl-L-leucine-modified polyethylenimine was successfully constructed through the EDC/NHS-mediated coupling reaction and employed as vectors to accomplish p53 gene delivery using HeLa (p53wt) and PC-3 cells (p53null) as models. Compared with PEI25K, the derivatives exhibited lower cytotoxicity, protein adsorption and hemolytic activity, together with satisfactory pDNA condensation capability and gene transfection efficiency. After p53 transfection, MTT analysis confirmed that the cell proliferation was inhibited. Flow cytometric analysis showed that the derivative-mediated p53 delivery could induce stronger early apoptosis than PEI25K and Lipofectamine(2000). Further, PC-3 cells showed higher sensitivity to the exogenous p53 transfection than HeLa cells. The mechanism for inducing apoptosis was determined to be up-regulation of p53 expression at both mRNA and protein levels using RT-PCR and western blotting analysis. Expression level and activity analysis of caspase-3, -8 and -9, and mitochondrial membrane potential measurement revealed that p53 transfection mediated by these derivatives facilitated early apoptosis of tumor cells via a mitochondria-dependent apoptosis pathway. Thus, the derivatives showed potential as biocompatible carriers for realizing effective tumor gene therapy. PMID:26322477

  3. Changes in N-acetyl-B-D-glucosaminidase and B-glucuronidase activities in milk during bovine mastitis.

    PubMed Central

    Nagahata, H; Saito, S; Noda, H

    1987-01-01

    To determine the N-acetyl-B-D-glucosaminidase (NAGase) and B-glucuronidase (B-Gase) activities in mastitic milk, basic enzyme assay conditions, distribution of NAGase and B-Gase, comparison of their activities with California Mastitis Test scores, and the effects of the milking process on their enzyme activities were examined. The mean NAGase and B-Gase activities in milk macrophages were about threefold higher than those of milk and blood polymorphonuclear cells. Very little NAGase activity appeared to be associated with blood mononuclear cells, whereas a relatively higher B-Gase activity was observed. California Mastitis Test scores of each group (1 to 5) appeared to be well correlated (r = 0.86 for NAGase and 0.92 for B-Gase) with the levels of NAGase and B-Gase activity. The milking process was least effective in the normal milk, but some variations of enzyme activities during milking in mastitic milk were found. Changes in NAGase and B-Gase activities in quarter milk were well monitored during the course of clinical mastitis. PMID:3567747

  4. Inhibition of sulfur mustard-increased protease activity by niacinamide, N-acetyl-L-cysteine or dexamethasone

    SciTech Connect

    Cowan, F.M.; Broomfield, C.A.; Smith, W.J.

    1991-03-11

    The pathologic mechanism of sulfur mustard-induced skin vesication is as yet undefined. Papirmeister et al. have postulated a biochemical mechanism for sulfur mustard-induced cutaneous injury involving sequelae of DNA alkylation, metabolic disruption resulting in NAD+ depletion and activation of protease. The authors have utilized a chromogenic peptide substrate assay to establish that human peripheral blood lymphocytes exposed 24 hr previously to sulfur mustard exhibited an increase in proteolytic activity. Doses of compounds known to alter the biochemical events associated with sulfur mustard exposure or reduce protease activity were tested in this system for their ability to block the sulfur mustard-induced protease activity. Treatment with niacinamide 1 hr after or with N-acetyl-L-cysteine or dexamethasone 24 hr prior to sulfur mustard exposure resulted in a decrease of 39%, 33% and 42% respectively of sulfur mustard-increased protease activity. These data suggest that therapeutic intervention into the biochemical pathways that culminate in protease activation might serve as an approach to treatment of sulfur mustard-induced pathology.

  5. Identification of the Enzyme Responsible for N-Acetylation of Norfloxacin by Microbacterium sp. Strain 4N2-2

    PubMed Central

    Kim, Dae-Wi; Feng, Jinhui; Chen, Huizhong; Kweon, Ohgew; Gao, Yuan; Yu, Li-Rong; Burrowes, Vanessa J.

    2013-01-01

    Microbacterium sp. 4N2-2, isolated from a wastewater treatment plant, converts the antibacterial fluoroquinolone norfloxacin to N-acetylnorfloxacin and three other metabolites. Because N-acetylation results in loss of antibacterial activity, identification of the enzyme responsible is important for understanding fluoroquinolone resistance. The enzyme was identified as glutamine synthetase (GS); N-acetylnorfloxacin was produced only under conditions associated with GS expression. The GS gene (glnA) was cloned, and the protein (53 kDa) was heterologously expressed and isolated. Optimal conditions and biochemical properties (Km and Vmax) of purified GS were characterized; the purified enzyme was inhibited by Mn2+, Mg2+, ATP, and ADP. The contribution of GS to norfloxacin resistance was shown by using a norfloxacin-sensitive Escherichia coli strain carrying glnA derived from Microbacterium sp. 4N2-2. The GS of Microbacterium sp. 4N2-2 was shown to act as an N-acetyltransferase for norfloxacin, which produced low-level norfloxacin resistance. Structural and docking analysis identified potential binding sites for norfloxacin at the ADP binding site and for acetyl coenzyme A (acetyl-CoA) at a cleft in GS. The results suggest that environmental bacteria whose enzymes modify fluoroquinolones may be able to survive in the presence of low fluoroquinolone concentrations. PMID:23104417

  6. Catabolism and detoxification of 1-aminoalkylphosphonic acids: N-acetylation by the phnO gene product.

    PubMed

    Hove-Jensen, Bjarne; McSorley, Fern R; Zechel, David L

    2012-01-01

    In Escherichia coli uptake and catabolism of organophosphonates are governed by the phnCDEFGHIJKLMNOP operon. The phnO cistron is shown to encode aminoalkylphosphonate N-acetyltransferase, which utilizes acetylcoenzyme A as acetyl donor and aminomethylphosphonate, (S)- and (R)-1-aminoethylphosphonate, 2-aminoethyl- and 3-aminopropylphosphonate as acetyl acceptors. Aminomethylphosphonate, (S)-1-aminoethylphosphonate, 2-aminoethyl- and 3-aminopropylphosphonate are used as phosphate source by E. coli phn(+) strains. 2-Aminoethyl- or 3-aminopropylphosphonate but not aminomethylphosphonate or (S)-1-aminoethylphosphonate is used as phosphate source by phnO strains. Neither phn(+) nor phnO strains can use (R)-1-aminoethylphosphonate as phosphate source. Utilization of aminomethylphosphonate or (S)-1-aminoethylphosphonate requires the expression of phnO. In the absence of phnO-expression (S)-1-aminoethylphosphonate is bacteriocidal and rescue of phnO strains requires the simultaneous addition of d-alanine and phosphate. An intermediate of the carbon-phosphorus lyase pathway, 5'-phospho-α-d-ribosyl 1'-(2-N-acetamidoethylphosphonate), a substrate for carbon-phosphorus lyase, was found to accumulate in cultures of a phnP mutant strain. The data show that the physiological role of N-acetylation by phnO-specified aminoalkylphosphonate N-acetyltransferase is to detoxify (S)-1-aminoethylphosphonate, an analog of d-alanine, and to prepare (S)-1-aminoethylphosphonate and aminomethylphosphonate for utilization of the phosphorus-containing moiety. PMID:23056305

  7. Differential effects of N-acetyl-aspartyl-glutamate on synaptic and extrasynaptic NMDA receptors are subunit- and pH-dependent in the CA1 region of the mouse hippocampus.

    PubMed

    Khacho, Pamela; Wang, Boyang; Ahlskog, Nina; Hristova, Elitza; Bergeron, Richard

    2015-10-01

    Ischemic strokes cause excessive release of glutamate, leading to overactivation of N-methyl-d-aspartate receptors (NMDARs) and excitotoxicity-induced neuronal death. For this reason, inhibition of NMDARs has been a central focus in identifying mechanisms to avert this extensive neuronal damage. N-acetyl-aspartyl-glutamate (NAAG), the most abundant neuropeptide in the brain, is neuroprotective in ischemic conditions in vivo. Despite this evidence, the exact mechanism underlying its neuroprotection, and more specifically its effect on NMDARs, is currently unknown due to conflicting results in the literature. Here, we uncover a pH-dependent subunit-specific action of NAAG on NMDARs. Using whole-cell electrophysiological recordings on acute hippocampal slices from adult mice and on HEK293 cells, we found that NAAG increases synaptic GluN2A-containing NMDAR EPSCs, while effectively decreasing extrasynaptic GluN2B-containing NMDAR EPSCs in physiological pH. Intriguingly, the results of our study further show that in low pH, which is a physiological occurrence during ischemia, NAAG depresses GluN2A-containing NMDAR EPSCs and amplifies its inhibitory effect on GluN2B-containing NMDAR EPSCs, as well as upregulates the surface expression of the GluN2A subunit. Altogether, our data demonstrate that NAAG has differential effects on NMDAR function based on subunit composition and pH. These findings suggest that the role of NAAG as a neuroprotective agent during an ischemic stroke is likely mediated by its ability to reduce NMDAR excitation. The inhibitory effect of NAAG on NMDARs and its enhanced function in acidic conditions make NAAG a prime therapeutic agent for the treatment of ischemic events. PMID:26303888

  8. Insulin Aspart (rDNA Origin) Injection

    MedlinePlus

    ... unless it is used in an external insulin pump. In patients with type 2 diabetes, insulin aspart ... also can be used with an external insulin pump. Before using insulin aspart in a pump system, ...

  9. N-acetyl-5-N,4-O-oxazolidinone-protected sialyl sulfoxide: an α-selective sialyl donor with Tf2O/(Tol)2SO in dichloromethane.

    PubMed

    Gu, Zhen-yuan; Zhang, Jia-xin; Xing, Guo-wen

    2012-06-01

    Sweet as sugar: Sialyl sulfoxide protected by N-acetyl-5-N,4-O-oxazolidinone was readily prepared, and its coupling to various sugar acceptors was investigated. When the reaction was promoted by Tf(2)O/(Tol)(2)SO, efficient and highly α-selective sialylation yielded α(2,6), α(2,3), and α(2,4) glycosidic linkages between sialic acid and glucose/glacotose. PMID:22488903

  10. A modeling study for structure features of β-N-acetyl-D-hexosaminidase from Ostrinia furnacalis and its novel inhibitor allosamidin: species selectivity and multi-target characteristics.

    PubMed

    Wang, Yanli; Liu, Tian; Yang, Qing; Li, Zhong; Qian, Xuhong

    2012-04-01

    Insect β-N-acetyl-D-hexosaminidase, a chitin degrading enzyme, is physiologically important during the unique life cycle of the insect. OfHex1, a β-N-acetyl-D-hexosaminidase from the insect, Ostrinia furna, which was obtained by our laboratory (Gen Bank No.: ABI81756.1), was studied by molecular modeling as well as by molecular docking with its inhibitor, allosamidin. 3D model of OfHex1 was built through the ligand-supported homology modeling approach. The binding modes of its substrate and inhibitor were proposed through docking and cluster analysis. The pocket's size and shape of OfHex1 differ from that of human β-N-acetyl-D-hexosaminidase, which determined that allosamidin can selectively inhibit OfHex1 instead of human β-N-acetyl-D-hexosaminidase. Moreover, the multi-target characteristics of allosamidin that inhibit enzymes from different families, OfHex1 (EC 3.2.1.52; GH20) and chitinase (EC 3.2.1.14; GH18), were compared. The common -1/+1 sugar-binding site of chitinase and OfHex1, and the -2/-3 sugar-binding site in chitinase contribute to the binding of allosamidin. This work, at molecular level, proved that OfHex1 could be a potential species-specific target for novel green pesticide design and also provide the possibility to develop allosamidin or its derivatives as a new type of insecticide to 'hit two birds with one stone', which maybe become a novel strategy in pest control. PMID:22177554

  11. The structure of putative N-acetyl glutamate kinase from Thermus thermophilus reveals an intermediate active site conformation of the enzyme.

    PubMed

    Sundaresan, Ramya; Ragunathan, Preethi; Kuramitsu, Seiki; Yokoyama, Shigeyuki; Kumarevel, Thirumananseri; Ponnuraj, Karthe

    2012-04-13

    The de novo biosynthesis of arginine in microorganisms and plants is accomplished via several enzymatic steps. The enzyme N-acetyl glutamate kinase (NAGK) catalyzes the phosphorylation of the γ-COO(-) group of N-acetyl-L-glutamate (NAG) by adenosine triphosphate (ATP) which is the second rate limiting step in arginine biosynthesis pathway. Here we report the crystal structure of putative N-acetyl glutamate kinase (NAGK) from Thermus thermophilus HB8 (TtNAGK) determined at 1.92Å resolution. The structural analysis of TtNAGK suggests that the dimeric quaternary state of the enzyme and arginine insensitive nature are similar to mesophilic Escherichia coli NAGK. These features are significantly different from its thermophilic homolog Thermatoga maritima NAGK which is hexameric and arginine-sensitive. TtNAGK is devoid of its substrates but contains two sulfates at the active site. Very interestingly the active site of the enzyme adopts a conformation which is not completely open or closed and likely represents an intermediate stage in the catalytic cycle unlike its structural homologs, which all exist either in the open or closed conformation. Engineering arginine biosynthesis pathway enzymes for the production of l-arginine is an important industrial application. The structural comparison of TtNAGK with EcNAGK revealed the structural basis of thermostability of TtNAGK and this information could be very useful to generate mutants of NAGK with increased overall stability. PMID:22452987

  12. Studies on the metabolism of 4-fluoroaniline and 4-fluoroacetanilide in rat: formation of 4-acetamidophenol (paracetamol) and its metabolites via defluorination and N-acetylation.

    PubMed

    Scarfe, G B; Tugnait, M; Wilson, I D; Nicholson, J K

    1999-02-01

    1. The urinary metabolic fate of 4-fluoroaniline (4-FA) and 1-[13C]-4-fluoroacetanilide (4-FAA) has been studied using NMR-based methods after 50 and 100 mg kg(-1) i.p. doses respectively to the male Sprague-Dawley rat. 2. 4-FA was both ortho- and para-hydroxylated. The major metabolite produced by ortho-hydroxylation was 2-amino-5-fluorophenylsulphate accounting for approximately 30% of the dose. Of the dose, approximately 10% was excreted via para-hydroxylation and the resulting defluorinated metabolites were N-acetylated and excreted as sulphate (major), glucuronide (minor) and N-acetyl-cysteinyl (minor) conjugates of 4-acetamidophenol (paracetamol). 3. The major route of metabolism of 1-[13C]-4-FAA was N-deacetylation and the metabolites excreted in the urine were qualitatively identical to 4-FA. The paracetamol metabolites produced via para-hydroxylation were also a product of N-deacetylation and reacetylation, as the [13C]-label was not retained. 4. These studies demonstrate the value of [13C]-labelling in understanding the contribution of N-acetylation, and futile deacetylation-reacetylation reactions, in aniline metabolism. In addition, this work sheds new light on the metabolic lability of certain aromatic fluorine substituents. PMID:10199596

  13. Synthesis and characterization of N-parinaroyl analogs of ganglioside GM3 and de-N-acetyl GM3. Interactions with the EGF receptor kinase

    NASA Technical Reports Server (NTRS)

    Song, W.; Welti, R.; Hafner-Strauss, S.; Rintoul, D. A.; Spooner, B. S. (Principal Investigator)

    1993-01-01

    A specific plasma membrane glycosphingolipid, known as ganglioside GM3, can regulate the intrinsic tyrosyl kinase activity of the epidermal growth factor (EGF) receptor; this modulation is not associated with alterations in hormone binding to the receptor. GM3 inhibits EGF receptor tyrosyl kinase activity in detergent micelles, in plasma membrane vesicles, and in whole cells. In addition, immunoaffinity-purified EGF receptor preparations contain ganglioside GM3 (Hanai et al. (1988) J. Biol. Chem. 263, 10915-10921), implying that the glycosphingolipid is intimately associated with the receptor kinase in cell membranes. Both the nature of this association and the molecular mechanism of kinase inhibition remain to be elucidated. In this report, we describe the synthesis of a fluorescent analog of ganglioside GM3, in which the native fatty acid was replaced with trans-parinaric acid. This glycosphingolipid inhibited the receptor kinase activity in a manner similar to that of the native ganglioside. A modified fluorescent glycosphingolipid, N-trans-parinaroyl de-N-acetyl ganglioside GM3, was also prepared. This analog, like the nonfluorescent de-N-acetyl ganglioside GM3, had no effect on receptor kinase activity. Results from tryptophan fluorescence quenching and steady-state anisotropy measurements in membranes containing these fluorescent probes and the human EGF receptor were consistent with the notion that GM3, but not de-N-acetyl GM3, interacts specifically with the receptor in intact membranes.

  14. The effect of substitution of the N-acetyl groups of N-acetylgalactosamine residues in chondroitin sulfate on its degradation by chondroitinase ABC.

    PubMed

    Madhunapantula, Subbarao V; Achur, Rajeshwara N; Bhavanandan, Veer P; Gowda, D Channe

    2007-11-01

    Chondroitinase ABC is a lyase that degrades chondroitin sulfate, dermatan sulfate and hyaluronic acid into disaccharides. The purpose of this study was to determine the ability of chondroitinase ABC to degrade chondroitin sulfate in which the N-acetyl groups are substituted with different acyl groups. The bovine tracheal chondroitin sulfate A (bCSA) was N-deacetylated by hydrazinolysis, and the free amino groups derivatized into N-formyl, N-propionyl, N-butyryl, N-hexanoyl or N-benzoyl amides. Treatment of the N-acyl or N-benzoyl derivatives of bCSA with chondroitinase ABC and analysis of the products showed that the N-formyl, N-hexanoyl and N-benzoyl derivatives are completely resistant to the enzyme. In contrast, the N-propionyl or N-butyryl derivatives were degraded into disaccharides with slower kinetics compared to that of unmodified bCSA. The rate of degradation of bCSA derivatives by the enzyme was found to be in the order of N-acetyl>N-propionyl>N-butyryl bCSA. These results have important implications for understanding the interaction of N-acetyl groups of glycosaminoglycans with chondroitinase ABC. PMID:17533514

  15. 21 CFR 582.5017 - Aspartic acid.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Aspartic acid. 582.5017 Section 582.5017 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5017 Aspartic acid. (a) Product. Aspartic acid (L- and DL-forms). (b) Conditions of...

  16. 21 CFR 582.5017 - Aspartic acid.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Aspartic acid. 582.5017 Section 582.5017 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5017 Aspartic acid. (a) Product. Aspartic acid (L- and DL-forms). (b) Conditions of...

  17. 21 CFR 582.5017 - Aspartic acid.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Aspartic acid. 582.5017 Section 582.5017 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5017 Aspartic acid. (a) Product. Aspartic acid (L- and DL-forms). (b) Conditions of...

  18. 21 CFR 582.5017 - Aspartic acid.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Aspartic acid. 582.5017 Section 582.5017 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5017 Aspartic acid. (a) Product. Aspartic acid (L- and DL-forms). (b) Conditions of...

  19. 21 CFR 582.5017 - Aspartic acid.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Aspartic acid. 582.5017 Section 582.5017 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5017 Aspartic acid. (a) Product. Aspartic acid (L- and DL-forms). (b) Conditions of...

  20. N-Acetyl-Seryl-Aspartyl-Lysyl-Proline: mechanisms of renal protection in mouse model of systemic lupus erythematosus

    PubMed Central

    Liao, Tang-Dong; Nakagawa, Pablo; Janic, Branislava; D'Ambrosio, Martin; Worou, Morel E.; Peterson, Edward L.; Rhaleb, Nour-Eddine; Yang, Xiao-Ping

    2015-01-01

    Systemic lupus erythematosus is an autoimmune disease characterized by the development of auto antibodies against a variety of self-antigens and deposition of immune complexes that lead to inflammation, fibrosis, and end-organ damage. Up to 60% of lupus patients develop nephritis and renal dysfunction leading to kidney failure. N-acetyl-seryl-aspartyl-lysyl-proline, i.e., Ac-SDKP, is a natural tetrapeptide that in hypertension prevents inflammation and fibrosis in heart, kidney, and vasculature. In experimental autoimmune myocarditis, Ac-SDKP prevents cardiac dysfunction by decreasing innate and adaptive immunity. It has also been reported that Ac-SDKP ameliorates lupus nephritis in mice. We hypothesize that Ac-SDKP prevents lupus nephritis in mice by decreasing complement C5-9, proinflammatory cytokines, and immune cell infiltration. Lupus mice treated with Ac-SDKP for 20 wk had significantly lower renal levels of macrophage and T cell infiltration and proinflammatory chemokine/cytokines. In addition, our data demonstrate for the first time that in lupus mouse Ac-SDKP prevented the increase in complement C5-9, RANTES, MCP-5, and ICAM-1 kidney expression and it prevented the decline of glomerular filtration rate. Ac-SDKP-treated lupus mice had a significant improvement in renal function and lower levels of glomerular damage. Ac-SDKP had no effect on the production of autoantibodies. The protective Ac-SDKP effect is most likely achieved by targeting the expression of proinflammatory chemokines/cytokines, ICAM-1, and immune cell infiltration in the kidney, either directly or via C5-9 proinflammatory arm of complement system. PMID:25740596

  1. MRI characterization of cobalt dichloride-N-acetyl cysteine (C4) contrast agent marker for prostate brachytherapy

    PubMed Central

    Lim, Tze Yee; Stafford, R Jason; Kudchadker, Rajat J; Sankaranarayanapillai, Madhuri; Ibbott, Geoffrey; Rao, Arvind; Martirosyan, Karen S; Frank, Steven J

    2014-01-01

    Brachytherapy, a radiotherapy technique for treating prostate cancer, involves the implantation of numerous radioactive seeds into the prostate. While the implanted seeds can be easily identified on a CT image, distinguishing the prostate and surrounding soft tissues is not as straightforward. Magnetic Resonance Imaging (MRI) offers superior anatomical delineation, but the seeds appear as dark voids and are difficult to identify, thus creating a conundrum. Cobalt dichloride-N-acetyl-cysteine (C4) has previously been shown to be promising as an encapsulated contrast agent marker. We performed spin-lattice relaxation time (T1) and spin-spin relaxation time (T2) measurements of C4 solutions with varying cobalt dichloride concentrations to determine the corresponding relaxivities, r1 and r2. These relaxation parameters were investigated at different field strengths, temperatures and orientations. T1 measurements obtained at 1.5 T and 3.0 T, as well as at room and body temperature, showed that r1 is field-independent and temperature-independent. Conversely, the T2 values at 3.0 T were shorter than at 1.5 T, while the T2 values at body temperature were slightly higher than at room temperature. By examining the relaxivities with the C4 vials aligned in three different planes, we found no orientation-dependence. With these relaxation characteristics, we aim to develop pulse sequences that will enhance the C4 signal against prostatic stroma. Ultimately, the use of C4 as a positive contrast agent marker will encourage the use of MRI to obtain an accurate representation of the radiation dose delivered to the prostate and surrounding normal anatomical structures. PMID:24778352

  2. MRI characterization of cobalt dichloride-N-acetyl cysteine (C4) contrast agent marker for prostate brachytherapy.

    PubMed

    Lim, Tze Yee; Stafford, R Jason; Kudchadker, Rajat J; Sankaranarayanapillai, Madhuri; Ibbott, Geoffrey; Rao, Arvind; Martirosyan, Karen S; Frank, Steven J

    2014-05-21

    Brachytherapy, a radiotherapy technique for treating prostate cancer, involves the implantation of numerous radioactive seeds into the prostate. While the implanted seeds can be easily identified on a computed tomography image, distinguishing the prostate and surrounding soft tissues is not as straightforward. Magnetic resonance imaging (MRI) offers superior anatomical delineation, but the seeds appear as dark voids and are difficult to identify, thus creating a conundrum. Cobalt dichloride-N-acetyl-cysteine (C4) has previously been shown to be promising as an encapsulated contrast agent marker. We performed spin-lattice relaxation time (T1) and spin-spin relaxation time (T2) measurements of C4 solutions with varying cobalt dichloride concentrations to determine the corresponding relaxivities, r1 and r2. These relaxation parameters were investigated at different field strengths, temperatures and orientations. T1 measurements obtained at 1.5 and 3.0 T, as well as at room and body temperature, showed that r1 is field-independent and temperature-independent. Conversely, the T2 values at 3.0 T were shorter than at 1.5 T, while the T2 values at body temperature were slightly higher than at room temperature. By examining the relaxivities with the C4 vials aligned in three different planes, we found no orientation-dependence. With these relaxation characteristics, we aim to develop pulse sequences that will enhance the C4 signal against prostatic stroma. Ultimately, the use of C4 as a positive contrast agent marker will encourage the use of MRI to obtain an accurate representation of the radiation dose delivered to the prostate and surrounding normal anatomical structures. PMID:24778352

  3. Arginine biosynthesis in Thermotoga maritima: characterization of the arginine-sensitive N-acetyl-L-glutamate kinase.

    PubMed

    Fernández-Murga, M Leonor; Gil-Ortiz, Fernando; Llácer, José L; Rubio, Vicente

    2004-09-01

    To help clarify the control of arginine synthesis in Thermotoga maritima, the putative gene (argB) for N-acetyl-L-glutamate kinase (NAGK) from this microorganism was cloned and overexpressed, and the resulting protein was purified and shown to be a highly thermostable and specific NAGK that is potently and selectively inhibited by arginine. Therefore, NAGK is in T. maritima the feedback control point of arginine synthesis, a process that in this organism involves acetyl group recycling and appears not to involve classical acetylglutamate synthase. The inhibition of NAGK by arginine was found to be pH independent and to depend sigmoidally on the concentration of arginine, with a Hill coefficient (N) of approximately 4, and the 50% inhibitory arginine concentration (I0.5) was shown to increase with temperature, approaching above 65 degrees C the I0.50 observed at 37 degrees C with the mesophilic NAGK of Pseudomonas aeruginosa (the best-studied arginine-inhibitable NAGK). At 75 degrees C, the inhibition by arginine of T. maritima NAGK was due to a large increase in the Km for acetylglutamate triggered by the inhibitor, but at 37 degrees C arginine also substantially decreased the Vmax of the enzyme. The NAGKs of T. maritima and P. aeruginosa behaved in gel filtration as hexamers, justifying the sigmoidicity and high Hill coefficient of arginine inhibition, and arginine or the substrates failed to disaggregate these enzymes. In contrast, Escherichia coli NAGK is not inhibited by arginine and is dimeric, and thus the hexameric architecture may be an important determinant of arginine sensitivity. Potential thermostability determinants of T. maritima NAGK are also discussed. PMID:15342584

  4. N-Acetyl-D-glucosamine decorated polymeric nanoparticles for targeted delivery of doxorubicin: Synthesis, characterization and in vitro evaluation.

    PubMed

    Tian, Baocheng; Ding, Yuanyuan; Han, Jian; Zhang, Jing; Han, Yuzhen; Han, Jingtian

    2015-06-01

    A novel targeting drug delivery system containing poly(styrene-alt-maleic anhydride)58-b-polystyrene130 (P(St-alt-MA)58-b-PSt130) as a copolymer backbone, N-acetyl glucosamine (NAG) as a targeting moiety was designed and synthesized. The NAG grafted copolymer (NAG-P(St-alt-MA)58-b-PSt130) was characterized by FTIR and (1)H NMR. The NAG-P(St-alt-MA)58-b-PSt130 nanoparticles exhibited spherical shapes with an average diameter about 56.27±0.43 nm, low critical micelle concentration of 0.028 mg/mL, negative zeta potential -41.46±0.99 mV, high drug loading 25.83±1.09% and encapsulation efficiency 69.69±3.98%. In vitro cell cytotoxicity was conducted to confirm the safety of the NAG-P(St-alt-MA)58-b-PSt130 nanoparticles. Confocal laser scanning microscopy (CLSM) and flow cytometry (FCM) results showed that the NAG targeting moiety enhanced the internalization and targeting ability of NAG-P(St-alt-MA)58-b-PSt130 nanoparticles. Anticancer activity toward MCF-7 cells and HT29 cells showed that DOX-loaded NAG-P(St-alt-MA)58-b-PSt130 nanoparticles exhibited a higher antitumor activity compared to DOX-loaded P(St-alt-MA)58-b-PSt130 nanoparticles, which could attribute to NAG receptor-mediated endocytosis. These results suggest that the biocompatible and non-toxic NAG-P(St-alt-MA)58-b-PSt130 nanoparticles may be used as an effective targeting drug delivery system for cancer therapy. PMID:25921641

  5. Benzyl-N-acetyl-alpha-D-galactosaminide induces a storage disease-like phenotype by perturbing the endocytic pathway.

    PubMed

    Ulloa, Fausto; Real, Francisco X

    2003-04-01

    The sugar analog O-benzyl-N-acetyl-alpha-d-galactosaminide (BG) is an inhibitor of glycan chain elongation and inhibits alpha2,3-sialylation in mucus-secreting HT-29 cells. Long-term exposure of these cells to BG is associated with the accumulation of apical glycoproteins in cytoplasmic vesicles. The mechanisms involved therein and the nature of the vesicles have not been elucidated. In these cells, a massive amount of BG metabolites is synthesized. Because sialic acid is mainly distributed apically in epithelial cells, it has been proposed that the BG-induced undersialylation of apical membrane glycoproteins is responsible for their intracellular accumulation due to a defect in anterograde traffic and that sialic acid may constitute an apical targeting signal. In this work, we demonstrate that the intracellular accumulation of membrane glycoproteins does not result mainly from defects in anterograde traffic. By contrast, in BG-treated cells, endocytosed membrane proteins were retained intracellularly for longer periods of time than in control cells and colocalized with accumulated MUC1 and beta(1) integrin in Rab7/lysobisphosphatidic acid(+) vesicles displaying features of late endosomes. The phenotype of BG-treated cells is reminiscent of that observed in lysosomal storage disorders. Sucrose induced a BG-like, lysosomal storage disease-like phenotype without affecting sialylation, indicating that undersialylation is not a requisite for the intracellular accumulation of membrane glycoproteins. Our findings strongly support the notion that the effects observed in BG-treated cells result from the accumulation of BG-derived metabolites and from defects in the endosomal pathway. We propose that abnormal subcellular distribution of membrane glycoproteins involved in cellular communication and/or signaling may also take place in lysosomal storage disorders and may contribute to their pathogenesis. PMID:12538583

  6. Isoflavone supplementation reduces DNA oxidative damage and increases O-β-N-acetyl-D-glucosaminidase activity in healthy women.

    PubMed

    Erba, Daniela; Casiraghi, M Cristina; Martinez-Conesa, Cristina; Goi, Giancarlo; Massaccesi, Luca

    2012-04-01

    Phenolic compounds are believed to boost the human antioxidant defense system and health; therefore, the aim of this research was to investigate the hypothesis that soy isoflavones (IFs) provide antioxidant protection in healthy women by evaluating DNA resistance to oxidative damage and O-β-N-acetyl-D-glucosaminidase (OGA) activity. An IF supplement (80 mg/d) was given to 9 postmenopausal women and 13 young women for 6 months and then stopped up to the 14th month. The women were allowed to consume their normal diet. Blood samples were collected at the beginning of the study after 2, 4, and 6 months and then at the 8th and 14th months. Plasma concentrations of genistein and daidzein, total antioxidant capacity, plasma vitamin status, markers of oxidative stress (red blood cell membrane fluidity, activity of the red blood cell cytosolic enzyme OGA and lymphocyte DNA susceptibility to oxidative stress), and serum lipid profile were analyzed. Analysis of variance for repeated measures was used for statistical analysis. Plasma concentrations of IFs rose significantly during the supplementation period, and plasma total antioxidant capacity increased in young women; membrane fluidity and OGA activity increased, and DNA oxidative damage decreased (P < .05) at 4 months, then returned to the basal level. There was a significant inverse correlation between DNA damage and plasma IF concentrations (P < .01). The results indicated a positive effect of IF supplementation on oxidative stress in women, thus suggesting that the healthful action ascribed to soy consumption may be partially related to the antioxidant potential of IFs. PMID:22575035

  7. N-acetyl cysteine prolonged the developmental ability of mouse two-cell embryos against oxidative stress at refrigerated temperatures.

    PubMed

    Horikoshi, Yuka; Takeo, Toru; Nakagata, Naomi

    2016-06-01

    Cold storage of two-cell embryos at refrigerated temperatures is a useful means to ship genetically engineered mice. We previously reported that M2 medium maintained the developmental ability of two-cell embryos for 48 h at 4 °C, and offspring were obtained from embryos transported by a courier service under refrigerated temperatures. The limitation of 48 h practically restricts the shipping destination of the embryos. To enhance the applicability of the cold-storage technique, prolonging the time to maintain developmental ability of the embryos is required. Oxidative stress may be a cause of the declining developmental ability of cold-stored embryos. However, the effect of oxidative stress on developmental ability of embryos has not been investigated. We examined intracellular glutathione (GSH) levels of cold-stored two-cell embryos to evaluate the effect of oxidative and investigated the efficacy of adding N-acetyl cysteine (NAC) to the preservation medium on the developmental ability of cold-stored embryos and transported two-cell embryos at refrigerated temperatures. Intracellular GSH levels of two-cell embryos decreased by cold storage for longer than 72 h, whereas NAC recovered this reduction and improved the developmental ability of embryos cold-stored for 96 h. In the transport experiment, the developmental rate of transported two-cell embryos to offspring was increased by adding NAC to the preservation medium. We found that NAC prolonged the storage period of two-cell embryos and maintained the developmental ability by alleviating the reduction of intracellular GSH. These findings will improve the technique of cold-storage of two-cell embryos to facilitate efficient transport of genetically engineered mice worldwide. PMID:27164059

  8. MRI characterization of cobalt dichloride-N-acetyl cysteine (C4) contrast agent marker for prostate brachytherapy

    NASA Astrophysics Data System (ADS)

    Lim, Tze Yee; Stafford, R. Jason; Kudchadker, Rajat J.; Sankaranarayanapillai, Madhuri; Ibbott, Geoffrey; Rao, Arvind; Martirosyan, Karen S.; Frank, Steven J.

    2014-05-01

    Brachytherapy, a radiotherapy technique for treating prostate cancer, involves the implantation of numerous radioactive seeds into the prostate. While the implanted seeds can be easily identified on a computed tomography image, distinguishing the prostate and surrounding soft tissues is not as straightforward. Magnetic resonance imaging (MRI) offers superior anatomical delineation, but the seeds appear as dark voids and are difficult to identify, thus creating a conundrum. Cobalt dichloride-N-acetyl-cysteine (C4) has previously been shown to be promising as an encapsulated contrast agent marker. We performed spin-lattice relaxation time (T1) and spin-spin relaxation time (T2) measurements of C4 solutions with varying cobalt dichloride concentrations to determine the corresponding relaxivities, r1 and r2. These relaxation parameters were investigated at different field strengths, temperatures and orientations. T1 measurements obtained at 1.5 and 3.0 T, as well as at room and body temperature, showed that r1 is field-independent and temperature-independent. Conversely, the T2 values at 3.0 T were shorter than at 1.5 T, while the T2 values at body temperature were slightly higher than at room temperature. By examining the relaxivities with the C4 vials aligned in three different planes, we found no orientation-dependence. With these relaxation characteristics, we aim to develop pulse sequences that will enhance the C4 signal against prostatic stroma. Ultimately, the use of C4 as a positive contrast agent marker will encourage the use of MRI to obtain an accurate representation of the radiation dose delivered to the prostate and surrounding normal anatomical structures.

  9. Electrochemical sensing of mesalazine and its N-acetylated metabolite in biological samples using functionalized carbon nanotubes.

    PubMed

    Nigović, Biljana; Sadiković, Mirela; Jurić, Sandra

    2016-01-15

    A rapid analytical method without the time-consuming separation step was developed to simultaneously determine mesalazine and its N-acetylated metabolite. A simply designed electrochemical sensor with functionalized carbon nanotubes in a Nafion matrix was constructed for this purpose. The presence of the nanocomposite modifier on the electrode surface significantly affects the voltammetric response of target analytes. The morphology of the modified surface was investigated by scanning electron microscopy. The effect of modifier amount on the sensor performance was investigated in order to obtain the most favorable response of mesalazine since it was found in lower concentration limits in real samples then its metabolite due to the rapid drug elimination and the slightly slower renal metabolite excretion. Under optimal conditions, the anodic peak currents measured by square-wave voltammetry increased linearly after short accumulation of 30s in the range of 5.0×10(-8)-2.5×10(-6)M and 1.0×10(-7)-5.0×10(-6)M for drug and metabolite, respectively. In addition to stable response, the sensor has excellent performance associated with high sensitivity (2.33×10(7) and 8.37×10(6)µAM(-1) for drug and metabolite, respectively). The synergistic effect of the carbon nanotubes and Nafion polymer film yielded detection limit of 1.2×10(-8)M for mesalazine and 2.6×10(-8)M for its metabolite that is comparable to known chromatographic methods. Due to the easy preparation and regeneration, the proposed sensor opens new opportunity for fast, simple and sensitive analysis of drug and its metabolite in human serum samples as well as direct quantification of mesalazine in delayed-release formulations. PMID:26592575

  10. Influence of Oct1/Oct2-Deficiency on Cisplatin-Induced Changes in Urinary N-Acetyl-β-D-Glucosaminidase

    PubMed Central

    Franke, Ryan M.; Kosloske, Ashley M.; Lancaster, Cynthia S.; Filipski, Kelly K.; Hu, Chaoxin; Zolk, Oliver; Mathijssen, Ron H.; Sparreboom, Alex

    2012-01-01

    Organic cation transporters have previously been implicated in cisplatin nephrotoxicity. In this study, we found that renal tubular secretion of cisplatin is abolished in mice lacking the Oct1 and Oct2 transporters [Oct1/2(−/−) mice], and these mice are protected from experiencing severe cisplatin-induced renal damage. Compared to wildtype mice, Oct1/2(−/−) mice also experienced a significantly decreased change in urinary activity of N-acetyl-β-D-glucosaminidase (NAG) following cisplatin administration (~4-fold, P=0.0016). A cutoff for cumulative urinary NAG activity of >0.4 AU was associated with a 21-fold increased odds for severe nephrotoxicity (P=0.0017), which in turn was linked with overall survival [hazard ratio (95%CI), 8.1 (2.1–31), P=0.0078]. Next, we screened 16 agents at varying concentrations for inhibitory potential against the human homolog transporter, OCT2, using transfected 293Flp-In cells. We focused further on the possible utility of cimetidine as an OCT2 inhibitor because of its strong potency (>95% inhibition), and because this agent is not routinely co-administered with cisplatin. In mice, we found that cimetidine inhibited cisplatin-induced urinary NAG activity changes to a degree significantly different from vehicle-control treated mice (P=0.016), but similar to that seen in Oct1/2(−/−) mice (P=0.91). Interestingly, cimetidine did not affect the uptake of cisplatin into SKOV-3 cells, the NCI60 cell line with the highest OCT2 expression. Collectively, this study suggests that OCT2 inhibitors can completely inhibit transporter-mediated uptake of cisplatin in renal proximal tubular cells, and subsequently ameliorate cisplatin nephrotoxicity without affecting the accumulation in tumor cells. PMID:20601443

  11. Diorganotin(IV) N-acetyl-L-cysteinate complexes: synthesis, solid state, solution phase, DFT and biological investigations.

    PubMed

    Pellerito, Lorenzo; Prinzivalli, Cristina; Casella, Girolamo; Fiore, Tiziana; Pellerito, Ornella; Giuliano, Michela; Scopelliti, Michelangelo; Pellerito, Claudia

    2010-07-01

    Diorganotin(IV) complexes of N-acetyl-L-cysteine (H(2)NAC; (R)-2-acetamido-3-sulfanylpropanoic acid) have been synthesized and their solid and solution-phase structural configurations investigated by FTIR, Mössbauer, (1)H, (13)C and (119)Sn NMR spectroscopy. FTIR results suggested that in R(2)Sn(IV)NAC (R = Me, Bu, Ph) complexes NAC(2-) behaves as dianionic tridentate ligand coordinating the tin(IV) atom, through ester-type carboxylate, acetate carbonyl oxygen atom and the deprotonated thiolate group. From (119)Sn Mössbauer spectroscopy it could be inferred that the tin atom is pentacoordinated, with equatorial R(2)Sn(IV) trigonal bipyramidal configuration. In DMSO-d(6) solution, NMR spectroscopic data showed the coordination of one solvent molecule to tin atom, while the coordination mode of the ligand through the ester-type carboxylate and the deprotonated thiolate group was retained in solution. DFT (Density Functional Theory) study confirmed the proposed structures in solution phase as well as the determination of the most probable stable ring conformation. Biological investigations showed that Bu(2)SnCl(2) and NAC2 induce loss of viability in HCC cells and only moderate effects in non-tumor Chang liver cells. NAC2 showed lower cytotoxic activity than Bu(2)SnCl(2), suggesting that the binding with NAC(2-) modulates the marked cytotoxic activity exerted by Bu(2)SnCl(2). Therefore, these novel butyl derivatives could represent a new class of anticancer drugs. PMID:20421134

  12. N-Acetyl-Seryl-Aspartyl-Lysyl-Proline: mechanisms of renal protection in mouse model of systemic lupus erythematosus.

    PubMed

    Liao, Tang-Dong; Nakagawa, Pablo; Janic, Branislava; D'Ambrosio, Martin; Worou, Morel E; Peterson, Edward L; Rhaleb, Nour-Eddine; Yang, Xiao-Ping; Carretero, Oscar A

    2015-05-15

    Systemic lupus erythematosus is an autoimmune disease characterized by the development of auto antibodies against a variety of self-antigens and deposition of immune complexes that lead to inflammation, fibrosis, and end-organ damage. Up to 60% of lupus patients develop nephritis and renal dysfunction leading to kidney failure. N-acetyl-seryl-aspartyl-lysyl-proline, i.e., Ac-SDKP, is a natural tetrapeptide that in hypertension prevents inflammation and fibrosis in heart, kidney, and vasculature. In experimental autoimmune myocarditis, Ac-SDKP prevents cardiac dysfunction by decreasing innate and adaptive immunity. It has also been reported that Ac-SDKP ameliorates lupus nephritis in mice. We hypothesize that Ac-SDKP prevents lupus nephritis in mice by decreasing complement C5-9, proinflammatory cytokines, and immune cell infiltration. Lupus mice treated with Ac-SDKP for 20 wk had significantly lower renal levels of macrophage and T cell infiltration and proinflammatory chemokine/cytokines. In addition, our data demonstrate for the first time that in lupus mouse Ac-SDKP prevented the increase in complement C5-9, RANTES, MCP-5, and ICAM-1 kidney expression and it prevented the decline of glomerular filtration rate. Ac-SDKP-treated lupus mice had a significant improvement in renal function and lower levels of glomerular damage. Ac-SDKP had no effect on the production of autoantibodies. The protective Ac-SDKP effect is most likely achieved by targeting the expression of proinflammatory chemokines/cytokines, ICAM-1, and immune cell infiltration in the kidney, either directly or via C5-9 proinflammatory arm of complement system. PMID:25740596

  13. Arginine Biosynthesis in Thermotoga maritima: Characterization of the Arginine-Sensitive N-Acetyl-l-Glutamate Kinase

    PubMed Central

    Fernández-Murga, M. Leonor; Gil-Ortiz, Fernando; Llácer, José L.; Rubio, Vicente

    2004-01-01

    To help clarify the control of arginine synthesis in Thermotoga maritima, the putative gene (argB) for N-acetyl-l-glutamate kinase (NAGK) from this microorganism was cloned and overexpressed, and the resulting protein was purified and shown to be a highly thermostable and specific NAGK that is potently and selectively inhibited by arginine. Therefore, NAGK is in T. maritima the feedback control point of arginine synthesis, a process that in this organism involves acetyl group recycling and appears not to involve classical acetylglutamate synthase. The inhibition of NAGK by arginine was found to be pH independent and to depend sigmoidally on the concentration of arginine, with a Hill coefficient (N) of ∼4, and the 50% inhibitory arginine concentration (I0.5) was shown to increase with temperature, approaching above 65°C the I0.50 observed at 37°C with the mesophilic NAGK of Pseudomonas aeruginosa (the best-studied arginine-inhibitable NAGK). At 75°C, the inhibition by arginine of T. maritima NAGK was due to a large increase in the Km for acetylglutamate triggered by the inhibitor, but at 37°C arginine also substantially decreased the Vmax of the enzyme. The NAGKs of T. maritima and P. aeruginosa behaved in gel filtration as hexamers, justifying the sigmoidicity and high Hill coefficient of arginine inhibition, and arginine or the substrates failed to disaggregate these enzymes. In contrast, Escherichia coli NAGK is not inhibited by arginine and is dimeric, and thus the hexameric architecture may be an important determinant of arginine sensitivity. Potential thermostability determinants of T. maritima NAGK are also discussed. PMID:15342584

  14. N-acetyl-cysteine and prostaglandin. Comparable protection against experimental ethanol injury in the stomach independent of mucus thickness.

    PubMed

    Henagan, J M; Smith, G S; Schmidt, K L; Miller, T A

    1986-12-01

    The role of barrier mucus in mediating the protective effects of 16,16 dimethyl PGE2 (dm PGE2) against ethanol-induced gastric injury, with and without concomitant treatment with N-acetyl-cysteine (NAC), a potent mucolytic agent, was evaluated. Fasted rats were orally administered either saline, 10 micrograms/kg dm PGE2, 20% NAC, or 10 micrograms/kg dm PGE2 plus 20% NAC. In the first study, the rats were killed 15 minutes later and their stomachs were removed and assayed for barrier mucus adherent to the gastric wall using the Alcian blue technique. In the second study, the rats were orally given 2 mL of absolute ethanol (EtOH) after receiving one of these pretreatment regimens, and 5 minutes later they were killed and their stomachs were evaluated histologically by light microscopy for the magnitude of EtOH injury. Although NAC significantly reduced the thickness of barrier mucus by 76% when compared with control animals, it did not adversely affect the ability of dm PGE2 to spare the deep epithelium from injury by EtOH. In fact, NAC was as effective a protective agent as dm PGE2. Neither agent prevented damage to the surface epithelium by EtOH, verifying previous studies regarding the protective effects of prostaglandins. These results indicate that both dm PGE2 and NAC prevent EtOH-induced damage to the deeper layers of the gastric mucosa independent of mucus gel layer thickness, suggesting that other mechanisms than mucus are involved in mediating this protection. PMID:3789839

  15. Transformation of acetaminophen by chlorination produces the toxicants 1,4-benzoquinone and N-acetyl-p-benzoquinone imine.

    PubMed

    Bedner, Mary; MacCrehan, William A

    2006-01-15

    The reaction of the common pain reliever acetaminophen (paracetamol, 4-acetamidophenol) with hypochlorite was investigated over time under conditions that simulate wastewater disinfection. Initially, the reaction was studied in pure water at neutral pH (7.0), a range of reaction times (2-90 min), and a molar excess of hypochlorite (2-57 times) relative to the acetaminophen concentration. The reaction was monitored using reversed-phase liquid chromatography (LC) with ultraviolet absorbance, electrochemical, and mass spectrometric detection. At 1 micromol/L (150 ppb) and 10 micromol/L (1.5 ppm) levels, acetaminophen readily reacted to form at least 11 discernible products, all of which exhibited greater LC retention than the parent. Two of the products were unequivocally identified as the toxic compounds 1,4-benzoquinone and N-acetyl-p-benzoquinone imine (NAPQI), which is the toxicant associated with lethality in acetaminophen overdoses. With a hypochlorite dose of 57 micromol/L (4 ppm as Cl2), 88% of the acetaminophen (10 micromol/L initial) was transformed in 1 h. The two quinoidal oxidation products 1,4-benzoquinone and NAPQI accounted for 25% and 1.5% of the initial acetaminophen concentration, respectively, at a 1 h reaction time. Other products that were identified included two ring chlorination products, chloro-4-acetamidophenol and dichloro-4-acetamidophenol, which combined were approximately 7% of the initial acetaminophen concentration at 1 h. The reaction was also studied in wastewater, where similar reactivity was noted. These results demonstrate that acetaminophen is likely to be transformed significantly during wastewater chlorination. The reactivity of the chlorine-transformation products was also studied with sulfite to simulate dechlorination, and 1,4-benzoquinone and NAPQI were completely reduced. PMID:16468397

  16. Engineering of Corynebacterium glutamicum for growth and L-lysine and lycopene production from N-acetyl-glucosamine.

    PubMed

    Matano, Christian; Uhde, Andreas; Youn, Jung-Won; Maeda, Tomoya; Clermont, Lina; Marin, Kay; Krämer, Reinhard; Wendisch, Volker F; Seibold, Gerd M

    2014-06-01

    Sustainable supply of feedstock has become a key issue in process development in microbial biotechnology. The workhorse of industrial amino acid production Corynebacterium glutamicum has been engineered towards utilization of alternative carbon sources. Utilization of the chitin-derived aminosugar N-acetyl-glucosamine (GlcNAc) for both cultivation and production with C. glutamicum has hitherto not been investigated. Albeit this organism harbors the enzymes N-acetylglucosamine-6-phosphatedeacetylase and glucosamine-6P deaminase of GlcNAc metabolism (encoded by nagA and nagB, respectively) growth of C. glutamicum with GlcNAc as substrate was not observed. This was attributed to the lack of a functional system for GlcNAc uptake. Of the 17 type strains of the genus Corynebacterium tested here for their ability to grow with GlcNAc, only Corynebacterium glycinophilum DSM45794 was able to utilize this substrate. Complementation studies with a GlcNAc-uptake deficient Escherichia coli strain revealed that C. glycinophilum possesses a nagE-encoded EII permease for GlcNAc uptake. Heterologous expression of the C. glycinophilum nagE in C. glutamicum indeed enabled uptake of GlcNAc. For efficient GlcNac utilization in C. glutamicum, improved expression of nagE with concurrent overexpression of the endogenous nagA and nagB genes was found to be necessary. Based on this strategy, C. glutamicum strains for the efficient production of the amino acid L-lysine as well as the carotenoid lycopene from GlcNAc as sole substrate were constructed. PMID:24668244

  17. N-acetyl-l-cysteine sensitizes pancreatic cancers to gemcitabine by targeting the NFκB pathway

    PubMed Central

    Qanungo, Suparna; Uys, Joachim D.; Manevich, Yefim; Distler, Anne M.; Shaner, Brooke; Hill, Elizabeth G.; Mieyal, John J.; Lemasters, John J.; Townsend, Danyelle M.; Nieminen, Anna-Liisa

    2015-01-01

    First-line therapy for pancreatic cancer is gemcitabine. Although tumors may initially respond to the gemcitabine treatment, soon tumor resistance develops leading to treatment failure. Previously, we demonstrated in human MIA PaCa-2 pancreatic cancer cells that N-acetyl-l-cysteine (NAC), a glutathione (GSH) precursor, prevents NFκB activation via S-glutathionylation of p65-NFκB, thereby blunting expression of survival genes. In this study, we documented the molecular sites of S-glutathionylation of p65, and we investigated whether NAC can suppress NFκB signaling and augment a therapeutic response to gemcitabine in vivo. Mass spectrometric analysis of S-glutathionylated p65-NFκB protein in vitro showed post-translational modifications of cysteines 38, 105, 120, 160 and 216 following oxidative and nitrosative stress. Circular dichroism revealed that S-glutathionylation of p65-NFκB did not change secondary structure of the protein, but increased tryptophan fluorescence revealed altered tertiary structure. Gemcitabine and NAC individually were not effective in decreasing MIA PaCa-2 tumor growth in vivo. However, combination treatment with NAC and gemcitabine decreased tumor growth by approximately 50%. NAC treatment also markedly enhanced tumor apoptosis in gemcitabine-treated mice. Compared to untreated tumors, gemcitabine treatment alone increased p65-NFκB nuclear translocation (3.7-fold) and DNA binding (2.5-fold), and these effects were blunted by NAC. In addition, NAC plus gemcitabine treatment decreased anti-apoptotic XIAP protein expression compared to gemcitabine alone. None of the treatments, however, affected extent of tumor hypoxia, as assessed by EF5 staining. Together, these results indicate that adjunct therapy with NAC prevents NFκB activation and improves gemcitabine chemotherapeutic efficacy. PMID:25257100

  18. Effects of N-acetyl-cysteine on endothelial function and inflammation in patients with type 2 diabetes mellitus

    PubMed Central

    Jeremias, Allen; Soodini, Geetha; Gelfand, Eli; Xu, Yizhen; Stanton, Robert C.; Horton, Edward S.; Cohen, David J.

    2009-01-01

    Endothelial dysfunction has been associated with premature vascular disease. There is increasing data that N-acetyl-cysteine (NAC) may prevent or improve endothelial dysfunction. The aim of this study was to assess the effects of NAC on endothelial function in patients with type 2 diabetes mellitus, a population at high risk for endothelial dysfunction. Twenty-four patients with diabetes mellitus were assigned randomly to initial therapy with either 900 mg NAC or placebo twice daily in a double-blind, cross-over study design. Flowmediated vasodilation (FMD) of the brachial artery was assessed at baseline, after four weeks of therapy, after a four-week wash-out period, and after another four weeks on the opposite treatment. Plasma and red blood cell glutathione levels and high-sensitivity C-reactive protein (CRP) were measured at all four visits. At baseline, FMD was moderately impaired (3.7±2.9%). There was no significant change in FMD after four weeks of NAC therapy as compared to placebo (0.1±3.6% vs. 1.2±4.2%). Similarly, there was no significant change in glutathione levels. However, median CRP decreased from 2.35 to 2.14 mg/L during NAC therapy (p=0.04), while it increased from 2.24 to 2.65 mg/L with placebo. No side effects were noted during the treatment period. In this double-blind, randomized cross-over study, four weeks of oral NAC therapy failed to improve endothelial dysfunction in patients with diabetes mellitus. However, NAC therapy decreased CRP levels, suggesting that this compound may have some efficacy in reducing systemic inflammation. PMID:21977284

  19. Biobreeding rat islets exhibit reduced antioxidative defense and N-acetyl cysteine treatment delays type 1 diabetes

    PubMed Central

    Bogdani, Marika; Henschel, Angela M.; Kansra, Sanjay; Fuller, Jessica M.; Geoffrey, Rhonda; Jia, Shuang; Kaldunski, Mary L.; Pavletich, Scott; Prosser, Simon; Chen, Yi-Guang; Lernmark, Åke; Hessner, Martin J.

    2014-01-01

    Islet-level oxidative stress has been proposed as a trigger for type 1 diabetes (T1D), and release of cytokines by infiltrating immune cells further elevates reactive oxygen species (ROS), exacerbating β cell duress. To identify genes/mechanisms involved with diabeto-genesis at the β cell level, gene expression profiling and targeted follow-up studies were used to investigate islet activity in the biobreeding (BB) rat. Forty-day-old spontaneously diabetic lymphopenic BB DRlyp/lyp rats (before T cell insulitis) as well as nondiabetic BB DR+/+ rats, nondiabetic but lymphopenic F344lyp/lyp rats, and healthy Fischer (F344) rats were examined. Gene expression profiles of BB rat islets were highly distinct from F344 islets and under-expressed numerous genes involved in ROS metabolism, including glutathione S-transferase (GST) family members (Gstm2, Gstm4, Gstm7, Gstt1, Gstp1, and Gstk1), superoxide dismutases (Sod2 and Sod3), peroxidases, and peroxiredoxins. This pattern of under-expression was not observed in brain, liver, or muscle. Compared with F344 rats, BB rat pancreata exhibited lower GST protein levels, while plasma GST activity was found significantly lower in BB rats. Systemic administration of the antioxidant N-acetyl cysteine to DRlyp/lyp rats altered abundances of peripheral eosinophils, reduced severity of insulitis, and significantly delayed but did not prevent diabetes onset. We find evidence of β cell dysfunction in BB rats independent of T1D progression, which includes lower expression of genes related to antioxidative defense mechanisms during the pre-onset period that may contribute to overall T1D susceptibility. PMID:23111281

  20. Reactive oxygen species scavenger N-acetyl cysteine reduces methamphetamine-induced hyperthermia without affecting motor activity in mice

    PubMed Central

    Sanchez-Alavez, Manuel; Bortell, Nikki; Galmozzi, Andrea; Conti, Bruno; Marcondes, Maria Cecilia G

    2015-01-01

    Hyperthermia is a potentially lethal side effect of Methamphetamine (Meth) abuse, which involves the participation of peripheral thermogenic sites such as the Brown Adipose Tissue (BAT). In a previous study we found that the anti-oxidant N-acetyl cysteine (NAC) can prevent the high increase in temperature in a mouse model of Meth-hyperthermia. Here, we have further explored the ability of NAC to modulate Meth-induced hyperthermia in correlation with changes in BAT. We found that NAC treatment in controls causes hypothermia, and, when administered prior or upon the onset of Meth-induced hyperthermia, can ameliorate the temperature increase and preserve mitochondrial numbers and integrity, without affecting locomotor activity. This was different from Dantrolene, which decreased motor activity without affecting temperature. The effects of NAC were seen in spite of its inability to recover the decrease of mitochondrial superoxide induced in BAT by Meth. In addition, NAC did not prevent the Meth-induced decrease of BAT glutathione. Treatment with S-adenosyl-L-methionine, which improves glutathione activity, had an effect in ameliorating Meth-induced hyperthermia, but also modulated motor activity. This suggests a role for the remaining glutathione for controlling temperature. However, the mechanism by which NAC operates is independent of glutathione levels in BAT and specific to temperature. Our results show that, in spite of the absence of a clear mechanism of action, NAC is a pharmacological tool to examine the dissociation between Meth-induced hyperthermia and motor activity, and a drug of potential utility in treating the hyperthermia associated with Meth-abuse. PMID:26346736

  1. N-acetyl-L-cysteine sensitizes pancreatic cancers to gemcitabine by targeting the NFκB pathway.

    PubMed

    Qanungo, Suparna; Uys, Joachim D; Manevich, Yefim; Distler, Anne M; Shaner, Brooke; Hill, Elizabeth G; Mieyal, John J; Lemasters, John J; Townsend, Danyelle M; Nieminen, Anna-Liisa

    2014-09-01

    First-line therapy for pancreatic cancer is gemcitabine. Although tumors may initially respond to the gemcitabine treatment, soon tumor resistance develops leading to treatment failure. Previously, we demonstrated in human MIA PaCa-2 pancreatic cancer cells that N-acetyl-l-cysteine (NAC), a glutathione (GSH) precursor, prevents NFκB activation via S-glutathionylation of p65-NFκB, thereby blunting expression of survival genes. In this study, we documented the molecular sites of S-glutathionylation of p65, and we investigated whether NAC can suppress NFκB signaling and augment a therapeutic response to gemcitabine in vivo. Mass spectrometric analysis of S-glutathionylated p65-NFκB protein in vitro showed post-translational modifications of cysteines 38, 105, 120, 160 and 216 following oxidative and nitrosative stress. Circular dichroism revealed that S-glutathionylation of p65-NFκB did not change secondary structure of the protein, but increased tryptophan fluorescence revealed altered tertiary structure. Gemcitabine and NAC individually were not effective in decreasing MIA PaCa-2 tumor growth in vivo. However, combination treatment with NAC and gemcitabine decreased tumor growth by approximately 50%. NAC treatment also markedly enhanced tumor apoptosis in gemcitabine-treated mice. Compared to untreated tumors, gemcitabine treatment alone increased p65-NFκB nuclear translocation (3.7-fold) and DNA binding (2.5-fold), and these effects were blunted by NAC. In addition, NAC plus gemcitabine treatment decreased anti-apoptotic XIAP protein expression compared to gemcitabine alone. None of the treatments, however, affected extent of tumor hypoxia, as assessed by EF5 staining. Together, these results indicate that adjunct therapy with NAC prevents NFκB activation and improves gemcitabine chemotherapeutic efficacy. PMID:25257100

  2. Quantitative LC-MS/MS determination of flupirtine, its N-acetylated and two mercapturic acid derivatives in man.

    PubMed

    Scheuch, Eberhard; Methling, Karen; Bednarski, Patrick J; Oswald, Stefan; Siegmund, Werner

    2015-01-01

    The non-opiate analgesic drug flupirtine was shown in vitro to undergo hydrolysis followed by N-acetylation to form D13223, glucuronidation and conjugation with glutathione to form the stable mercapturic acid derivatives M-424 and M-466. To quantify flupirtine and its metabolites in samples obtained in a clinical study in healthy subjects selected on their genotype of NAT2, UGT1A1 and GSTP1, two LC-MS/MS methods were developed. The validation range for flupirtine and D-13223 in serum was 0.5-500 ng/ml. For urine and feces, the validation ranges for flupirtine and D-13223 were 20-5000 ng/ml and 5.0-5000 ng/ml, respectively. M-424 and M-466 could be quantified in urine between 5.0 and 5000 ng/ml. Free flupirtine and D-13223 were separated from serum, urine and feces with liquid-liquid extraction. For flupirtine and D-13223, the chromatography was performed on a XTerra C18 column isocratically with a mobile phase consisting of ammonium formate buffer (pH 3.5mM) and acetonitrile (50:50; v/v), for M-466 and M-424 a Synergi(®) Fusion-RP column was used and a linear gradient method with water/HCOOH (pH 3) and acetonitrile. The mass spectrometer operated both with electro spray ionization in positive multiple reaction monitoring mode. The developed methods fulfilled the current FDA criteria on bioanalytical method validation for accuracy (error: -16.9 to 11.2%), precision (1.2-13.4%), recovery, stability and matrix effects over the observed analytical range. Thus, the methods were suitable to quantify flupirtine absorption and metabolic disposition in man after single intravenous and oral dosing (100mg) and repeated oral administration (400mg once daily). PMID:25459937

  3. Investigation of the therapeutic potential of N-acetyl cysteine and the tools used to define nigrostriatal degeneration in vivo.

    PubMed

    Nouraei, Negin; Zarger, Lauren; Weilnau, Justin N; Han, Jimin; Mason, Daniel M; Leak, Rehana K

    2016-04-01

    The glutathione precursor N-acetyl-l-cysteine (NAC) is currently being tested on Parkinson's patients for its neuroprotective properties. Our studies have shown that NAC can elicit protection in glutathione-independent manners in vitro. Thus, the goal of the present study was to establish an animal model of NAC-mediated protection in which to dissect the underlying mechanism. Mice were infused intrastriatally with the oxidative neurotoxicant 6-hydroxydopamine (6-OHDA; 4μg) and administered NAC intraperitoneally (100mg/kg). NAC-treated animals exhibited higher levels of the dopaminergic terminal marker tyrosine hydroxylase (TH) in the striatum 10d after 6-OHDA. As TH expression is subject to stress-induced modulation, we infused the tracer FluoroGold into the striatum to retrogradely label nigrostriatal projection neurons. As expected, nigral FluoroGold staining and cell counts of FluoroGold(+) profiles were both more sensitive measures of nigrostriatal degeneration than measurements relying on TH alone. However, NAC failed to protect dopaminergic neurons 3weeks following 6-OHDA, an effect verified by four measures: striatal TH levels, nigral TH levels, nigral TH(+) cell counts, and nigral FluoroGold levels. Some degree of mild toxicity of FluoroGold and NAC was evident, suggesting that caution must be exercised when relying on FluoroGold as a neuron-counting tool and when designing experiments with long-term delivery of NAC-such as clinical trials on patients with chronic disorders. Finally, the strengths and limitations of the tools used to define nigrostriatal degeneration are discussed. PMID:26879220

  4. Structural Diversity Within the Mononuclear and Binuclear Active Sites of N-Acetyl-D-Glucosamine-6-Phosphate Deacetylase

    SciTech Connect

    Hall,R.; Brown, S.; Fedorov, A.; Fedorov, E.; Xu, C.; Babbitt, P.; Almo, S.; Raushel, F.

    2007-01-01

    NagA catalyzes the hydrolysis of N-acetyl-D-glucosamine-6-phosphate to D-glucosamine-6-phosphate and acetate. X-ray crystal structures of NagA from Escherichia coli were determined to establish the number and ligation scheme for the binding of zinc to the active site and to elucidate the molecular interactions between the protein and substrate. The three-dimensional structures of the apo-NagA, Zn-NagA, and the D273N mutant enzyme in the presence of a tight-binding N-methylhydroxyphosphinyl-D-glucosamine-6-phosphate inhibitor were determined. The structure of the Zn-NagA confirms that this enzyme binds a single divalent cation at the beta-position in the active site via ligation to Glu-131, His-195, and His-216. A water molecule completes the ligation shell, which is also in position to be hydrogen bonded to Asp-273. In the structure of NagA bound to the tight binding inhibitor that mimics the tetrahedral intermediate, the methyl phosphonate moiety has displaced the hydrolytic water molecule and is directly coordinated to the zinc within the active site. The side chain of Asp-273 is positioned to activate the hydrolytic water molecule via general base catalysis and to deliver this proton to the amino group upon cleavage of the amide bond of the substrate. His-143 is positioned to help polarize the carbonyl group of the substrate in conjunction with Lewis acid catalysis by the bound zinc. The inhibitor is bound in the {alpha}-configuration at the anomeric carbon through a hydrogen bonding interaction of the hydroxyl group at C-1 with the side chain of His-251. The phosphate group of the inhibitor attached to the hydroxyl at C-6 is ion paired with Arg-227 from the adjacent subunit. NagA from Thermotoga maritima was shown to require a single divalent cation for full catalytic activity.

  5. Structural diversity within the mononuclear and binuclear active sites of N-acetyl-D-glucosamine-6-phosphate deacetylase.

    PubMed

    Hall, Richard S; Brown, Shoshana; Fedorov, Alexander A; Fedorov, Elena V; Xu, Chengfu; Babbitt, Patricia C; Almo, Steven C; Raushel, Frank M

    2007-07-10

    NagA catalyzes the hydrolysis of N-acetyl-d-glucosamine-6-phosphate to d-glucosamine-6-phosphate and acetate. X-ray crystal structures of NagA from Escherichia coli were determined to establish the number and ligation scheme for the binding of zinc to the active site and to elucidate the molecular interactions between the protein and substrate. The three-dimensional structures of the apo-NagA, Zn-NagA, and the D273N mutant enzyme in the presence of a tight-binding N-methylhydroxyphosphinyl-d-glucosamine-6-phosphate inhibitor were determined. The structure of the Zn-NagA confirms that this enzyme binds a single divalent cation at the beta-position in the active site via ligation to Glu-131, His-195, and His-216. A water molecule completes the ligation shell, which is also in position to be hydrogen bonded to Asp-273. In the structure of NagA bound to the tight binding inhibitor that mimics the tetrahedral intermediate, the methyl phosphonate moiety has displaced the hydrolytic water molecule and is directly coordinated to the zinc within the active site. The side chain of Asp-273 is positioned to activate the hydrolytic water molecule via general base catalysis and to deliver this proton to the amino group upon cleavage of the amide bond of the substrate. His-143 is positioned to help polarize the carbonyl group of the substrate in conjunction with Lewis acid catalysis by the bound zinc. The inhibitor is bound in the alpha-configuration at the anomeric carbon through a hydrogen bonding interaction of the hydroxyl group at C-1 with the side chain of His-251. The phosphate group of the inhibitor attached to the hydroxyl at C-6 is ion paired with Arg-227 from the adjacent subunit. NagA from Thermotoga maritima was shown to require a single divalent cation for full catalytic activity. PMID:17567048

  6. Effectiveness of N-acetyl cysteine, 2% chlorhexidine, and their combination as intracanal medicaments on Enterococcus faecalis biofilm

    PubMed Central

    Palaniswamy, Udayakumar; Lakkam, Surender Ram; Arya, Shikha; Aravelli, Swathi

    2016-01-01

    Aim: The purpose of this study was to evaluate the antibacterial efficacies of 2% chlorhexidine (CHX), N-acetyl cysteine (NAC) and assess their synergistic or antagonist action as intracanal medicament. Materials and Methods: Agar diffusion test was performed with 2% CHX, NAC, and their combination against E. faecalis planktonic cells. The diameters of the zones of bacterial inhibition were measured and recorded for each solution. The assay was further extended to 2 weeks old E. faecalis dentinal biofilm. Sixteen freshly extracted teeth were vertically sectioned into two halves resulting in a total of 32 samples. The samples were inoculated with bacterial suspension and incubated at 37°C for 2 weeks for biofilm formation. The samples were then divided into four experimental groups with 8 samples in each group. The samples were gently washed in saline and placed in culture wells containing the test solutions, i.e., 2% CHX, NAC, a combination of 2% CHX and NAC in 1:1 ratio, and a control group containing saline. The biofilm formed on the root canal surface were removed with a sterile scalpel and inoculated on blood agar plates to check for the formation of E. faecalis colonies. Statistical Analysis: For agar diffusion test, data were analyzed statistically using one-way analysis of variance and then by post-hoc Scheffe's test to compare the antimicrobial efficacy between the groups. Statistical analysis was not done for the cultures obtained from the biofilm as there was no growth in all the three test groups except the control group, i.e., saline. Results: In agar diffusion test, among the three groups tested, 2% CHX and NAC showed almost equal zones of inhibition whereas maximum inhibition was shown by a combination of NAC and 2% CHX suggesting a synergistic action. The results obtained were highly significant (P < 0.001) for the combination of medicament when compared to individual test group. In culture analysis, which was done for the biofilm, no growth was

  7. N-Acetyl Cysteine May Support Dopamine Neurons in Parkinson's Disease: Preliminary Clinical and Cell Line Data

    PubMed Central

    Monti, Daniel A.; Zabrecky, George; Kremens, Daniel; Liang, Tsao-Wei; Wintering, Nancy A.; Cai, Jingli; Wei, Xiatao; Bazzan, Anthony J.; Zhong, Li; Bowen, Brendan; Intenzo, Charles M.; Iacovitti, Lorraine; Newberg, Andrew B.

    2016-01-01

    Backgound The purpose of this study was to assess the biological and clinical effects of n-acetyl-cysteine (NAC) in Parkinson’s disease (PD). Methods The overarching goal of this pilot study was to generate additional data about potentially protective properties of NAC in PD, using an in vitro and in vivo approach. In preparation for the clinical study we performed a cell tissue culture study with human embryonic stem cell (hESC)-derived midbrain dopamine (mDA) neurons that were treated with rotenone as a model for PD. The primary outcome in the cell tissue cultures was the number of cells that survived the insult with the neurotoxin rotenone. In the clinical study, patients continued their standard of care and were randomized to receive either daily NAC or were a waitlist control. Patients were evaluated before and after 3 months of receiving the NAC with DaTscan to measure dopamine transporter (DAT) binding and the Unified Parkinson’s Disease Rating Scale (UPDRS) to measure clinical symptoms. Results The cell line study showed that NAC exposure resulted in significantly more mDA neurons surviving after exposure to rotenone compared to no NAC, consistent with the protective effects of NAC previously observed. The clinical study showed significantly increased DAT binding in the caudate and putamen (mean increase ranging from 4.4% to 7.8%; p<0.05 for all values) in the PD group treated with NAC, and no measurable changes in the control group. UPDRS scores were also significantly improved in the NAC group (mean improvement of 12.9%, p = 0.01). Conclusions The results of this preliminary study demonstrate for the first time a potential direct effect of NAC on the dopamine system in PD patients, and this observation may be associated with positive clinical effects. A large-scale clinical trial to test the therapeutic efficacy of NAC in this population and to better elucidate the mechanism of action is warranted. Trial Registration ClinicalTrials.gov NCT02445651

  8. Determination of N-acetyl-S-(N-methylcarbamoyl)cysteine (AMCC) in the general population using gas chromatography-mass spectrometry.

    PubMed

    Käfferlein, H U; Angerer, J

    1999-10-01

    Carbamoylation of glutathione, peptides and DNA is thought to be one of the most important reactions occurring in an organism after exposure to nitrosoureas, methylformamides or isocyanates. The carcinogenic effects of carbamoylation are not yet fully clarified. Although carbamoylation is known to occur after occupational exposure, it has never been reported in the general population. To clarify the situation, we investigated the levels of N-acetyl-S-(N-methylcarbamoyl)cysteine (AMCC) in urine samples from persons without occupational exposure using a sensitive and specific method (gas chromatography-mass spectrometry, GC-MS). AMCC is the degradation product of N-methylcarbamoylated glutathione. The clean-up procedure of urine samples includes two liquid-liquid extraction steps and solid phase extraction using a cation-exchange resin to separate AMCC from other urinary components. N,N-Dimethylpropionic acid amide (DMPA) is used as internal standard. During the preparation of the samples, AMCC is converted to ethyl-N-methylcarbamate (EMC) in the presence of anhydrous potassium carbonate (K2CO3) and ethanol. The reliability and accuracy of this method have been proven in detail. The relative standard deviation for the within-series imprecision for three different concentrations was determined to be between 10.9% and 14.3%, while the relative standard deviation for the between-day imprecision was between 11.3% and 14.8%. The mean recovery for AMCC was determined to be between 79.2% and 85.6%. The limit of detection for the simultaneous measurement of two fragment masses was 30 micrograms L-1. Using this GC-MS method, we analysed urine samples from 42 individuals of the general population in order to determine their urinary excretion of AMCC. It was identified in 40 samples. The mean concentration was 40 micrograms L-1. AMCC can be formed in two ways. The first possibility is the dietary intake of isothiocyanates, especially methyl isothiocyanate, which is a component

  9. Thiopurine metabolites variations during co-treatment with aminosalicylates for inflammatory bowel disease: Effect of N-acetyl transferase polymorphisms

    PubMed Central

    Stocco, Gabriele; Cuzzoni, Eva; De Iudicibus, Sara; Favretto, Diego; Malusà, Noelia; Martelossi, Stefano; Pozzi, Elena; Lionetti, Paolo; Ventura, Alessandro; Decorti, Giuliana

    2015-01-01

    AIM: To evaluate variation of the concentration of thiopurine metabolites after 5-aminosalicylate (5-ASA) interruption and the role of genetic polymorphisms of N-acetyl transferase (NAT) 1 and 2. METHODS: Concentrations of thioguanine nucleotides (TGN) and methymercaptopurine nucleotides (MMPN), metabolites of thiopurines, were measured by high performance liquid chromatography in 12 young patients (3 females and 9 males, median age 16 years) with inflammatory bowel disease (6 Crohn’s disease and 6 ulcerative colitis) treated with thiopurines (7 mercaptopurine and 5 azathioprine) and 5-ASA. Blood samples were collected one month before and one month after the interruption of 5-ASA. DNA was extracted and genotyping of NAT1, NAT2, inosine triphosphate pyrophosphatase (ITPA) and thiopurine methyl transferase (TPMT) genes was performed using PCR assays. RESULTS: Median TGN concentration before 5-ASA interruption was 270 pmol/8 x 108 erythrocytes (range: 145-750); after the interruption of the aminosalicylate, a 35% reduction in TGN mean concentrations (absolute mean reduction 109 pmol/8 × 108 erythrocytes) was observed (median 221 pmol/8 × 108 erythrocytes, range: 96-427, P value linear mixed effects model 0.0011). Demographic and clinical covariates were not related to thiopurine metabolites concentrations. All patients were wild-type for the most relevant ITPA and TPMT variants. For NAT1 genotyping, 7 subjects presented an allele combination corresponding to fast enzymatic activity and 5 to slow activity. NAT1 genotypes corresponding to fast enzymatic activity were associated with reduced TGN concentration (P value linear mixed effects model 0.033), putatively because of increased 5-ASA inactivation and consequent reduced inhibition of thiopurine metabolism. The effect of NAT1 status on TGN seems to be persistent even after one month since the interruption of the aminosalicylate. No effect of NAT1 genotypes was shown on MMPN concentrations. NAT2 genotyping

  10. Effects of oral administration of N-acetyl-L-cysteine: a multi-biomarker study in smokers.

    PubMed

    Van Schooten, Frederik Jan; Besaratinia, Ahmad; Besarati Nia, Ahmad; De Flora, Silvio; D'Agostini, Francesco; Izzotti, Alberto; Camoirano, Anna; Balm, Alfons J M; Dallinga, Jan Willem; Bast, Aalt; Haenen, Guido R M M; Van't Veer, Laura; Baas, Paul; Sakai, Harumasa; Van Zandwijk, Nico

    2002-02-01

    N-Acetyl-L-cysteine (NAC) has been shown to exert cancer-protective mechanisms and effects in experimental models. We report here the results of a randomized, double-blind, placebo-controlled, Phase II chemoprevention trial with NAC in healthy smoking volunteers. The subjects were supplemented daily with 2 x 600 mg of oral tablets of NAC (n = 20) or placebo (n = 21) for a period of 6 months, and internal dose markers [plasma and bronchoalveolar lavage (BAL) fluid cotinine, urine mutagenicity], biologically effective dose markers [smoking-related DNA adducts and hemoglobin (Hb) adducts], and biological response markers (micronuclei frequency and antioxidants scavenging capacity) were assessed at both pre- and postsupplementation times (T(0) and T(1), respectively). Overall, the internal dose markers remained unchanged at T(1) as compared with T(0) in both NAC and placebo groups. When quantifying the biologically effective dose markers, we observed an inhibitory effect of NAC toward the formation of lipophilic-DNA adducts (5.18 +/- 0.73 versus 4.08 +/- 1.03/10(8) nucleotides; mean +/- SE; P = 0.05) as well as of 7,8-dihydro-8-oxo-2'-deoxyguanosine adducts in BAL cells (3.9 +/- 0.6 versus 2.3 +/- 0.2/10(5) nucleotides; P = 0.003). There was no effect of NAC on the formation of lipophilic-DNA adducts in peripheral blood lymphocytes or polycyclic aromatic hydrocarbon-DNA adducts in mouth floor/buccal mucosa cells or 4-aminobiphenyl-Hb adducts. Likewise, quantification of the biological response markers showed an inhibitory effect of NAC on the frequency of micronuclei in mouth floor and in soft palate cells (1.3 +/- 0.2 versus 0.9 +/- 0.2; P = 0.001) and a stimulating effect of NAC on plasma antioxidant scavenging capacity (393 +/- 14 versus 473 +/- 19 microM Trolox; P = 0.1) but not on BAL fluid antioxidant scavenging capacity. We conclude that NAC has the potential to impact upon tobacco smoke carcinogenicity in humans because it can modulate certain cancer

  11. N-Acetyl-beta-D-glucopyranosylamine 6-phosphate is a specific inhibitor of glycogen-bound protein phosphatase 1.

    PubMed Central

    Board, M

    1997-01-01

    Previous work has shown that the C-1-substituted glucose-analogue N-acetyl-beta-D-glucopyranosylamine (1-GlcNAc) is a competitive inhibitor of glycogen phosphorylase (GP) and stimulates the inactivation of this enzyme by GP phosphatase. In addition to its effects on GP, 1-GlcNAc also prevents the glucose-led activation of glycogen synthase (GS) in whole hepatocytes. Such an effect on GS was thought to be due to the formation of 1-GlcNAc-6-P by the action of glucokinase within the hepatocyte [Board, Bollen, Stalmans, Kim, Fleet and Johnson (1995) Biochem. J. 311, 845-852]. To investigate this possibility further, a pure preparation of 1-GlcNAc-6-P was synthesized. The effects of the phosphorylated glucose analogue on the activity of protein phosphatase 1 (PP1), the enzyme responsible for dephosphorylation and activation of GS, are reported. During the present study, 1-GlcNAc-6-P inhibited the activity of the glycogen-bound form of PP1, affecting both the GSb phosphatase and GPa phosphatase activities. A level of 50% inhibition of GSb phosphatase activity was achieved with 85 microM 1-GlcNAc-6-P in the absence of Glc-6-P and with 135 microM in the presence of 10 mM Glc-6-P. At either Glc-6-P concentration, 500 microM 1-GlcNAc-6-P completely inhibited activity. The Glc-6-P stimulation of the GPa phosphatase activity of PP1 was negated by 1-GlcNAc-6-P but there was no inhibition of the basal rate in the absence of Glc-6-P. 1-GlcNAc-6-P inhibition was specific for the glycogen-bound form of PP1 and did not inhibit the GSb phosphatase activity of the cytosolic form of the enzyme. The present work explains our previous observations on the inactivating effects on GS of incubating whole hepatocytes with 1-GlcNAc. These observations have their basis in the inhibition of glycogen-bound PP1 by 1-GlcNAc-6-P. A novel inhibitor of PP1, specific for the glycogen-bound form of the enzyme, is presented. PMID:9371733

  12. A novel mechanism for resistance to the antimetabolite N-phosphonoacetyl-L-aspartate by Helicobacter pylori.

    PubMed

    Burns, B P; Mendz, G L; Hazell, S L

    1998-11-01

    The mechanism of resistance to N-phosphonoacetyl-L-aspartate (PALA), a potent inhibitor of aspartate carbamoyltransferase (which catalyzes the first committed step of de novo pyrimidine biosynthesis), in Helicobacter pylori was investigated. At a 1 mM concentration, PALA had no effects on the growth and viability of H. pylori. The inhibitor was taken up by H. pylori cells and the transport was saturable, with a Km of 14.8 mM and a Vmax of 19.1 nmol min-1 microliters of cell water-1. By 31P nuclear magnetic resonance (NMR) spectroscopy, both PALA and phosphonoacetate were shown to have been metabolized in all isolates of H. pylori studied. A main metabolic end product was identified as inorganic phosphate, suggesting the presence of an enzyme activity which cleaved the carbon-phosphorus (C-P) bonds. The kinetics of phosphonate group cleavage was saturable, and there was no evidence for substrate inhibition at higher concentrations of either compound. C-P bond cleavage activity was temperature dependent, and the activity was lost in the presence of the metal chelator EDTA. Other cleavages of PALA were observed by 1H NMR spectroscopy, with succinate and malate released as main products. These metabolic products were also formed when N-acetyl-L-aspartate was incubated with H. pylori lysates, suggesting the action of an aspartase. Studies of the cellular location of these enzymes revealed that the C-P bond cleavage activity was localized in the soluble fraction and that the aspartase activity appeared in the membrane-associated fraction. The results suggested that the two H. pylori enzymes transformed the inhibitor into noncytotoxic products, thus providing the bacterium with a mechanism of resistance to PALA toxicity which appears to be unique. PMID:9791105

  13. Aspartate protects Lactobacillus casei against acid stress.

    PubMed

    Wu, Chongde; Zhang, Juan; Du, Guocheng; Chen, Jian

    2013-05-01

    The aim of this study was to investigate the effect of aspartate on the acid tolerance of L. casei. Acid stress induced the accumulation of intracellular aspartate in L. casei, and the acid-resistant mutant exhibited 32.5 % higher amount of aspartate than that of the parental strain at pH 4.3. Exogenous aspartate improved the growth performance and acid tolerance of Lactobacillus casei during acid stress. When cultivated in the presence of 50 mM aspartate, the biomass of cells increased 65.8 % compared with the control (without aspartate addition). In addition, cells grown at pH 4.3 with aspartate addition were challenged at pH 3.3 for 3 h, and the survival rate increased 42.26-fold. Analysis of the physiological data showed that the aspartate-supplemented cells exhibited higher intracellular pH (pHi), intracellular NH4 (+) content, H(+)-ATPase activity, and intracellular ATP pool. In addition, higher contents of intermediates involved in glycolysis and tricarboxylic acid cycle were observed in cells in the presence of aspartate. The increased contents of many amino acids including aspartate, arginine, leucine, isoleucine, and valine in aspartate-added cells may contribute to the regulation of pHi. Transcriptional analysis showed that the expression of argG and argH increased during acid stress, and the addition of aspartate induced 1.46- and 3.06-fold higher expressions of argG and argH, respectively, compared with the control. Results presented in this manuscript suggested that aspartate may protect L. casei against acid stress, and it may be used as a potential protectant during the production of probiotics. PMID:23292549

  14. Polarized spectroscopic elucidation of N-acetyl-L-cysteine, L-cysteine, L-cystine, L-ascorbic acid and a tool for their determination in solid mixtures.

    PubMed

    Koleva, Bojidarka; Spiteller, Michael; Kolev, Tsonko

    2010-01-01

    Method of linear polarized vibrational (both IR- and Raman) spectroscopy of oriented colloids in nematic host is applied on N-acetyl-L-cysteine, L-cysteine, L-cystine and L-ascorbic acid with a view to obtain experimental bands assignment and local structural elucidation in solid-state. Structural results are compared with available crystallographic data for all of the systems studied. Scopes and limitations of the polarized method are shown. Discussion on the correlation between polarized spectroscopic data and the space group type as well as the number of the molecules in the unit cell (Z) is performed. Compounds with monoclinic space group P2(1), containing Z = 1 (N-acetyl-L-cysteine) and 2 (L-cysteine and L-ascorbic acid) are elucidated. One of the rare for organic molecules, hexagonal P6(1)22 space group and Z = 6 (L: -cystine) is also elucidated. Experimental assignment of the characteristics frequencies is obtained, explaining the typical for the crystals Fermi-resonance, Fermy-Davydov and Davydov splitting effects. For first time in the literature we are reported the orientation of the solid-mixture in nematic host, using the trade product ACC (Hexal, Germany), containing mainly N-acetyl-L-cysteine and L-ascorbic acid. Quantitative IR-spectroscopic approach for determination of solid mixtures is presented as well. The intensity ratio between 1,716 cm(-1) (characteristic for N-acetyl-L-cysteine) and 990 cm(-1), (attributed N-acethyl-cysteine and vitamin C) is used. Linear regression analysis between content and the peak ratio data for ten solid-binary mixtures, leads to straight-line plot y = 1.08(2) (+/-0.04(9)) + (-0.11(4) +/- 0.01(1))x, where x = 1/X ( i ). Factor r of 0.9641 and a reliability of 98.85% are obtained. The analysis of ACC 200 (Hexal, Germany) show that the IR measurements leads to standard deviation of 0.010 and 0.011 at P about 0.0500 for the systems and a confidence of >98.77(1)%. PMID:19212805

  15. A molecular biomarker for disruption of crustacean molting: the N-acetyl-beta-glucosaminidase mRNA in the epidermis of the fiddler crab.

    PubMed

    Meng, Yanling; Zou, Enmin

    2009-05-01

    Several environmentally persistent chemicals have been found to be capable of disrupting crustacean molting. Considering the importance of molting in the life of crustaceans, there is a need to develop a molecular biomarker that can reflect the disrupting effects of contaminants on ecdysteroid signaling in crustaceans. N-acetyl-beta-glucosaminidase (NAG) is a chitinolytic enzyme found in crustacean epidermis. The results of the present investigation show that the transcription of NAG gene in the epidermis of the fiddler crab, Uca pugilator, is inducible by the molting hormone 20-hydroxyecdysone, which validates the use of NAG mRNA as a biomarker for molt-disrupting effects of xenobiotics. PMID:19156345

  16. Acetylated α-Tubulin Regulated by N-Acetyl-Seryl-Aspartyl-Lysyl-Proline(Ac-SDKP) Exerts the Anti-fibrotic Effect in Rat Lung Fibrosis Induced by Silica.

    PubMed

    Xiaojun, Wang; Yan, Liu; Hong, Xu; Xianghong, Zhang; Shifeng, Li; Dingjie, Xu; Xuemin, Gao; Lijuan, Zhang; Bonan, Zhang; Zhongqiu, Wei; Ruimin, Wang; Brann, Darrell; Fang, Yang

    2016-01-01

    Silicosis is the most serious occupational disease in China. The objective of this study was to screen various proteins related to mechanisms of the pathogenesis of silicosis underlying the anti-fibrotic effect of N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) using proteomic profile analysis. We also aimed to explore a potential mechanism of acetylated α-tubulin (α-Ac-Tub) regulation by Ac-SDKP. Two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/TOF MS) were used to assess the different protein expression profiles between control and silicosis rats treated with or without Ac-SDKP. Twenty-nine proteins were identified to be potentially involved in the progression of silicosis and the anti-fibrotic effect of Ac-SDKP. Our current study finds that 1) the lost expression of Ac-Tub-α may be a new mechanism in rat silicosis; 2) treatment of silicotic rats with N-acetyl-Seryl-Aspartyl-Lysyl-Proline (Ac-SDKP) inhibits myofibroblast differentiation and collagen deposition accompanied by stabilizing the expression of α-Ac-Tub in vivo and in vitro, which is related with deacetylase family member 6 (HDAC6) and α-tubulin acetyl transferase (α-TAT1). Our data suggest that α-Ac-Tub regulation by Ac-SDKP may potentially be a new anti-fibrosis mechanism. PMID:27577858

  17. A vibrational molecular force field of model compounds with biological interest. V. Harmonic dynamic of N-acetyl-α- D-glucosamine in the crystalline state

    NASA Astrophysics Data System (ADS)

    Kouach-Alix, I.; Vergoten, G.

    1994-07-01

    Combining the modified Urey—Bradley—Shimanouchi intramolecular potential energy function with an appropriate intermolecular energy function, normal coordinate calculations have been performed for N-acetyl-α- D-glucosamine in the crystalline state. The infrared spectra in the mid range (4000-500 cm -1) and the Raman spectra in 3500-20 cm -1 range were recorded. The overall agreement between the observed and calculated frequencies led to an average error of the order of 3.5 cm -1. The computed potential energy distribution was found to be compatible with previous assignments of D-glucose and D-galactose for the pyranose ring and for N-methylacetamide for the acetamido group. The set of force constants used for N-acetyl-α- D-glucosamine was approximately the same as that obtained for the glucose and N-methylacetamide respectively for the pyranose ring and the acetamido group, a difference existing only for the atoms involved in the anomeric and hydroxy groups.

  18. A Ribbon-like Structure in the Ejective Organelle of the Green Microalga Pyramimonas parkeae (Prasinophyceae) Consists of Core Histones and Polymers Containing N-acetyl-glucosamine.

    PubMed

    Yamagishi, Takahiro; Kurihara, Akira; Kawai, Hiroshi

    2015-11-01

    The green microalga, Pyramimonas parkeae (Prasinophyceae) has an ejective organelle containing a coiled ribbon structure resembling the ejectisome in Cryptophyta. This structure is discharged from the cell by a stimulus and extends to form a tube-like structure, but the molecular components of the structure have not been identified. Tricine-SDS-PAGE analysis indicated that the ribbon-like structure of P. parkeae contains some proteins and low molecular acidic polymers. Edman degradation, LC/MS/MS analyses and immunological studies demonstrated that their proteins are core histones (H3, H2A, H2B and H4). In addition, monosaccharide composition analysis of the ribbon-like structures and degradation by lysozyme strongly indicated that the ribbon-like structure consist of β (1-4) linked polymers containing N-acetyl-glucosamine. Purified polymers and recombinant histones formed glob-like or filamentous structures. Therefore we conclude that the ribbon-like structure of P. parkeae mainly consists of a complex of core histones (H3, H2A, H2B and H4) and polymers containing N-acetyl-glucosamine, and suggest to name the ejective organelle in P. parkeae the "histrosome" to distinguish it from the ejectisome in Cryptophyta. PMID:26398336

  19. Development of a N-acetyl-β-D-glucosaminidase (NAG) assay on a centrifugal lab-on-a-compact-disc (Lab-CD) platform.

    PubMed

    Tanaka, Yoshihide; Okuda, Seira; Sawai, Ayumi; Suzuki, Shigeo

    2012-01-01

    A centrifugal microfluidic platform, which is also known as lab-on-a-compact-disc (Lab-CD), was developed for use as a urinary N-acetyl-β-D-glucosaminidase (NAG) activity assay. In this work, Lab-CD design, centrifugal operations and analytical procedures were established. Automated liquid handling on Lab-CD processes, such as fluid transport, sample metering, mixing, and fluorescence detection are accomplished using a portable Lab-CD system. The linearity of the NAG assay using 4-methylumbelliferyl-N-acetyl-β-D-glucosaminide (4-MU-GlcNAc) was found to be acceptable in the range of 2.5 to 20 U L(-1); the relative standard deviations for the fluorescence intensity of eight samples (7.5 U L(-1)) was 6.4%. Clinical diagnostics is one of the most promising applications for Lab-CD technologies. All the benefits of miniaturization, such as reduced sample requirement, reduced reagent consumption and automation, are realized in this investigation. PMID:22232221

  20. Acetylated α-Tubulin Regulated by N-Acetyl-Seryl-Aspartyl-Lysyl-Proline(Ac-SDKP) Exerts the Anti-fibrotic Effect in Rat Lung Fibrosis Induced by Silica

    PubMed Central

    Xiaojun, Wang; Yan, Liu; Hong, Xu; Xianghong, Zhang; Shifeng, Li; Dingjie, Xu; Xuemin, Gao; Lijuan, Zhang; Bonan, Zhang; Zhongqiu, Wei; Ruimin, Wang; Brann, Darrell; Fang, Yang

    2016-01-01

    Silicosis is the most serious occupational disease in China. The objective of this study was to screen various proteins related to mechanisms of the pathogenesis of silicosis underlying the anti-fibrotic effect of N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) using proteomic profile analysis. We also aimed to explore a potential mechanism of acetylated α-tubulin (α-Ac-Tub) regulation by Ac-SDKP. Two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/TOF MS) were used to assess the different protein expression profiles between control and silicosis rats treated with or without Ac-SDKP. Twenty-nine proteins were identified to be potentially involved in the progression of silicosis and the anti-fibrotic effect of Ac-SDKP. Our current study finds that 1) the lost expression of Ac-Tub-α may be a new mechanism in rat silicosis; 2) treatment of silicotic rats with N-acetyl-Seryl-Aspartyl-Lysyl-Proline (Ac-SDKP) inhibits myofibroblast differentiation and collagen deposition accompanied by stabilizing the expression of α-Ac-Tub in vivo and in vitro, which is related with deacetylase family member 6 (HDAC6) and α-tubulin acetyl transferase (α-TAT1). Our data suggest that α-Ac-Tub regulation by Ac-SDKP may potentially be a new anti-fibrosis mechanism. PMID:27577858

  1. Immobilized enzymes to convert N-sulfo, N-acetyl heparosan to a critical intermediate in the production of bioengineered heparin.

    PubMed

    Xiong, Jian; Bhaskar, Ujjwal; Li, Guoyun; Fu, Li; Li, Lingyun; Zhang, Fuming; Dordick, Jonathan S; Linhardt, Robert J

    2013-09-10

    Heparin is a critically important anticoagulant drug that is prepared from pig intestine. In 2007-2008, there was a crisis in the heparin market when the raw material was adulterated with the toxic polysaccharide, oversulfated chondroitin sulfate, which was associated with 100 deaths in the U.S. alone. As the result of this crisis, our laboratory and others have been actively pursuing alternative sources for this critical drug, including synthetic heparins and bioengineered heparin. In assessing the bioengineering processing costs it has become clear that the use of both enzyme-catalyzed cofactor recycling and enzyme immobilization will be needed for commercialization. In the current study, we examine the use of immobilization of C₅-epimerase and 2-O-sulfotransferase involved in the first enzymatic step in the bioengineered heparin process, as well as arylsulfotransferase-IV involved in cofactor recycling in all three enzymatic steps. We report the successful immobilization of all three enzymes and their use in converting N-sulfo, N-acetyl heparosan into N-sulfo, N-acetyl 2-O-sulfo heparin. PMID:23835156

  2. The Escherichia coli G-fimbrial lectin protein participates both in fimbrial biogenesis and in recognition of the receptor N-acetyl-D-glucosamine.

    PubMed Central

    Saarela, S; Taira, S; Nurmiaho-Lassila, E L; Makkonen, A; Rhen, M

    1995-01-01

    The gafD gene encoding the N-acetyl-D-glucosamine-specific fimbrial lectin (adhesin) protein GafD of uropathogenic Escherichia coli was cloned and subjected to genetic analysis. The corresponding gene product was isolated as a MalE fusion protein. The lectin gene was identified with the aid of deletion mutagenesis; mutations in gafD impaired either receptor binding or both receptor binding and fimbria production, depending on the mutation created. All mutants converted to wild-type expressors when complemented in trans with the cloned intact gafD gene. The predicted 354-amino-acid sequence of GafD, deduced from the nucleotide sequence, is closely related to those of the fimbria-associated F17-G and F17b-G proteins coded for by enterotoxigenic and invasive E. coli strains. Isolated GafD was shown to recognize N-acetyl-D-glucosamine by virtue of specific binding to an immobilized receptor, thus proving directly that GafD is a sugar-binding protein. Our results indicate that GafD as such is sufficient for receptor recognition and that the protein also participates in fimbrial biogenesis. PMID:7883703

  3. Colorimetric detection of iron ions (III) based on the highly sensitive plasmonic response of the N-acetyl-L-cysteine-stabilized silver nanoparticles.

    PubMed

    Gao, Xiaohui; Lu, Yizhong; He, Shuijian; Li, Xiaokun; Chen, Wei

    2015-06-16

    We report here a facile colorimetric sensor based on the N-acetyl-L-cysteine (NALC)-stabilized Ag nanoparticles (NALC-Ag NPs) for detection of Fe(3+) ions in aqueous solution. The Ag NPs with an average diameter of 6.55±1.0 nm are successfully synthesized through a simple method using sodium borohydride as reducing agent and N-acetyl-L-cysteine as protecting ligand. The synthesized silver nanoparticles show a strong surface plasmon resonance (SPR) around 400 nm and the SPR intensity decreases with the increasing of Fe(3+) concentration in aqueous solution. Based on the linear relationship between SPR intensity and concentration of Fe(3+) ions, the as-synthesized water-soluble silver nanoparticles can be used for the sensitive and selective detection of Fe(3+) ions in water with a linear range from 80 nM to 80 μM and a detection limit of 80 nM. On the basis of the experimental results, a new detection mechanism of oxidation-reduction reaction between Ag NPs and Fe(3+) ions is proposed, which is different from previously reported mechanisms. Moreover, the NALC-Ag NPs could be applied to the detection of Fe(3+) ions in real environmental water samples. PMID:26002486

  4. Amino acid sequence and carbohydrate-binding analysis of the N-acetyl-D-galactosamine-specific C-type lectin, CEL-I, from the Holothuroidea, Cucumaria echinata.

    PubMed

    Hatakeyama, Tomomitsu; Matsuo, Noriaki; Shiba, Kouhei; Nishinohara, Shoichi; Yamasaki, Nobuyuki; Sugawara, Hajime; Aoyagi, Haruhiko

    2002-01-01

    CEL-I is one of the Ca2+-dependent lectins that has been isolated from the sea cucumber, Cucumaria echinata. This protein is composed of two identical subunits held by a single disulfide bond. The complete amino acid sequence of CEL-I was determined by sequencing the peptides produced by proteolytic fragmentation of S-pyridylethylated CEL-I. A subunit of CEL-I is composed of 140 amino acid residues. Two intrachain (Cys3-Cys14 and Cys31-Cys135) and one interchain (Cys36) disulfide bonds were also identified from an analysis of the cystine-containing peptides obtained from the intact protein. The similarity between the sequence of CEL-I and that of other C-type lectins was low, while the C-terminal region, including the putative Ca2+ and carbohydrate-binding sites, was relatively well conserved. When the carbohydrate-binding activity was examined by a solid-phase microplate assay, CEL-I showed much higher affinity for N-acetyl-D-galactosamine than for other galactose-related carbohydrates. The association constant of CEL-I for p-nitrophenyl N-acetyl-beta-D-galactosaminide (NP-GalNAc) was determined to be 2.3 x 10(4) M(-1), and the maximum number of bound NP-GalNAc was estimated to be 1.6 by an equilibrium dialysis experiment. PMID:11866098

  5. Urinary N-acetyl-β-d-Glucosaminidase Levels are Positively Correlated With 2-Hr Plasma Glucose Levels During Oral Glucose Tolerance Testing in Prediabetes

    PubMed Central

    Ouchi, Motoshi; Suzuki, Tatsuya; Hashimoto, Masao; Motoyama, Masayuki; Ohara, Makoto; Suzuki, Kazunari; Igari, Yoshimasa; Watanabe, Kentaro; Nakano, Hiroshi; Oba, Kenzo

    2012-01-01

    Background Urinary N-acetyl-β-D-glucosaminidase (NAG) excretion is increased in patients with impaired glucose tolerance (IGT). This study investigated when during the oral glucose tolerance test (OGTT) the plasma glucose, urine glucose, and insulin levels correlate most strongly with urinary N-acetyl-β-d-glucosaminidase (NAG) levels in prediabetic subjects. Methods The OGTT was administered to 80 subjects who had not yet received a diagnosis of diabetes mellitus (DM) and in whom HbA1c levels were ≤6.8% and fasting plasma glucose levels were <7.0 mmol/l. Forty-two subjects had normal glucose tolerance (NGT), 31 had impaired glucose tolerance (IGT), and 7 had DM according to World Health Organization criteria. Serum levels of cystatin C, the estimated glomerular filtration rate, the urinary albumin-to-creatinine (Cr) ratio, urinary and serum β2-microglobulin, and urinary NAG were measured as markers of renal function. Results NAG levels were significantly higher in subjects with DM and in subjects with IGT than in subjects with NGT. No significant associations were observed between glycemic status and other markers of renal function. Multiple linear regression analysis showed that the NAG level was positively correlated with plasma glucose levels at 120 min of the OGTT and was associated with the glycemic status of prediabetic patients. Conclusion These results suggest that postprandial hyperglycemia is an independent factor that causes renal tubular damage in prediabetes patients. PMID:23143631

  6. Nitrification of Aspartate by Aspergillus flavus

    PubMed Central

    Hatcher, H. J.; Schmidt, E. L.

    1971-01-01

    Heterotrophic conversion of l-aspartic acid to nitrification products by Aspergillus flavus was studied in a replacement incubation system. Numerous amino acids supported nitrification; aspartate and glutamate were about equivalent as the best sources of nitrate. Addition of sodium bicarbonate to the incubation system substantially enhanced nitrate formation for all nitrifiable amino acids except aspartic acid, but the basis for the bicarbonate effect is obscure. The yield of nitrate from l-aspartate was not approached by forms of aspartic acid resulting from substitution on the beta carbon, the amino nitrogen, or the gamma carboxyl group or by aspartate presented as the d-configuration. There was no relationship between nitrate formation and the occurrence of such possible intermediates as nitrite, bound hydroxylamine, ammonia, aspergillic acid, and beta-nitropropionic acid. Uniformly labeled 14C-l-aspartate that was nitrified in replacement incubation led to no accumulation of label in possible nitrification products in the culture filtrate. Label was found in components of the mycelium after acid hydrolysis, with heaviest accumulation in what appeared to be glucosamine and an unidentified compound, possibly acetylglucosamine. Detectable label was redistributed into serine, glycine, and threonine. Images PMID:5549699

  7. Four homochiral coordination polymers contain N-acetyl-L-tyrosine and different N-donor ligand: Influence of metal cations, ancillary ligands and coordination modes

    SciTech Connect

    Li, Meng-Li; Song, Hui-Hua

    2013-10-15

    Using the chiral ligand N-acetyl-L-tyrosine (Hacty) and maintaining identical reaction conditions, Zn(II), Co(II), and Cd(II) salts provided four novel homochiral coordination polymers ([Zn(acty)(bipy){sub 2}(H{sub 2}O){sub 2}]·NO{sub 3}·2H{sub 2}O){sub n}1, ([Co(acty)(bipy){sub 2}(H{sub 2}O){sub 2}]·NO{sub 3}·2H{sub 2}O){sub n}2, ([Cd(acty){sub 2}(bipy)H{sub 2}O]·H{sub 2}O){sub n}3, and ([Cd(acty)(bpe){sub 2}(Ac)]·6H{sub 2}O){sub n}4 (bipy=4,4′-bipyridine; bpe=1,2-di(4-pyridyl)ethane) in the presence of ancillary ligands. Compounds 1 and 2 are isostructural 1D chain structures. The neighboring chains are further linked into a 3D supramolecular structure via π⋯π stacking and hydrogen bond interactions. Compound 3 shows a 2D network and 4 generates 1D infinite chains along the c-axis. Compounds 3 and 4 are further connected into 3D supramolecular network by hydrogen bond interactions. More importantly, coordination in acyl oxygen atoms and ancillary ligands (bpe) as monodentate decorating ligands in 4 are rarely reported. Ancillary ligands and metal cations significantly influence the structure of the complexes. The photoluminescence properties of 1, 3, and 4 were studied at room temperature. Circular dichroism (CD) of the complexes have been investigated. - Graphical abstract: Four new homochiral coordination polymers were prepared and structurally characterized, which investigate the influence of the ancillary ligands and metal ions on the design and synthesis of coordination polymers. Display Omitted - Highlights: • It is rarely reported that the chiral coordination polymers prepared with N-acetyl-L-tyrosine ligands. • The alkalescent acetyl oxygen atom is difficult to participate in coordination but it is happened in the N-acetyl-L-tyrosine ligands. • The ancillary ligands (4,4′-bipy and bpe) are present in an unusual coordination modes, monodentate decorating ligands in 1, 2 and 4. • Structure comparative analyses results indicate that the

  8. [A short path to synthesis of 4-deoxy-4-fluoroglucosaminides: methylumbelliferyl N-acetyl-4-deoxy-4-fluoro-beta-D-glucosaminide].

    PubMed

    Markina, N A; Voznyĭ, Ia V

    2008-01-01

    A convenient method of synthesis of 1,6-anhydro-4-deoxy-2-O-tosyl-4-fluoro-beta-D-glucopyranose by fusion of 1,6;3,4-dianhydro-2-O-tosyl-beta-D-galactopyranose with 2,4,6-trimethylpyridinium fluoride was found. By successive action of ammonia, methyl trifluoroacetate, and acetic anhydride, the resulting compound was transformed into 1,6-anhydro-3-O-acetyl-2,4-dideoxy-2-trifluoroacetamido-4-fluoro-beta-D-glucopyranose, which was converted into 3,6-di-O-acetyl-2,4-dideoxy-2-trifluoroacetamido-4-fluoro-alpha-D-glucopyranosyl fluoride by the reaction with HF/Py. The resulting fluoride was further used as a glycosyl donor in the synthesis of methylumbelliferyl N-acetyl-4-deoxy-4-fluoro-beta-D-glucosaminide. PMID:18695726

  9. The Interaction of a Carbohydrate-Binding Module from a Clostridium perfringens N-Acetyl-beta-hexosaminidase with its Carbohydrate Receptor

    SciTech Connect

    Ficko-Blean,E.; Boraston, A.

    2006-01-01

    Clostridium perfringens is a notable colonizer of the human gastrointestinal tract. This bacterium is quite remarkable for a human pathogen by the number of glycoside hydrolases found in its genome. The modularity of these enzymes is striking as is the frequent occurrence of modules having amino acid sequence identity with family 32 carbohydrate-binding modules (CBMs), often referred to as F5/8 domains. Here we report the properties of family 32 CBMs from a C. perfringens N-acetyl-{beta}-hexosaminidase. Macroarray, UV difference, and isothermal titration calorimetry binding studies indicate a preference for the disaccharide LacNAc ({beta}-d-galactosyl-1,4-{beta}-d-N-acetylglucosamine). The molecular details of the interaction of this CBM with galactose, LacNAc, and the type II blood group H-trisaccharide are revealed by x-ray crystallographic studies at resolutions of 1.49, 2.4, and 2.3 Angstroms, respectively.

  10. Design, Synthesis and Biological Evaluation of N-Acetyl-S-(pchlorophenylcarbamoyl)cysteine and Its Analogs as a Novel Class of Anticancer Agents

    PubMed Central

    Chen, Wei; Seefeldt, Teresa; Young, Alan; Zhang, Xiaoying; Guan, Xiangming

    2010-01-01

    N-Acetyl-S-(p-chlorophenylcarbamoyl)cysteine (NACC) was identified as a metabolite of sulofenur. Sulofenur was demonstrated to have broad activity against solid tumors in preclinical studies but exhibited disappointing clinical responses due to its high protein binding related adverse effects. NACC exhibited low protein binding and excellent activity against a sulofenur sensitive human colon cancer cell line. In this study, analogs of NACC were synthesized and evaluated with four human cancer cell lines. Two of the NACC analogs showed excellent activity against two human melanoma cell lines, while NACC remains the most potent of the series. All three compounds were more potent than dacarbazine, which is used extensively in treating melanoma. NACC was shown to induce apoptosis without affecting the cell cycle. Further, NACC exhibited low toxicity against monkey kidney cells. The selective anticancer activity, low toxicity, an unknown yet but unique anticancer mechanism and ready obtainability through synthesis make NACC and its analogs promising anticancer agents. PMID:21131205