Science.gov

Sample records for aldehyde conjugates cytosolic

  1. Stereoselective sulphate conjugation of racemic terbutaline by human liver cytosol.

    PubMed

    Walle, T; Walle, U K

    1990-07-01

    1. The enantioselectivity of the sulphation of racemic terbutaline by phenolsulphotransferases was examined in vitro using cytosol from human livers (n = 3) and [35S]-3'-phosphoadenosine-5'-phosphosulphate (PAP35S) as the sulphate donor. 2. The radioactive sulphate conjugate formed was isolated by h.p.l.c. and its enantiomers were separated intact by h.p.l.c. after chiral derivatization. 3. Sulphation of racemic terbutaline occurred with the same apparent Km value for both enantiomers (270 microM). The extent of sulphation of the (+)-enantiomer was double that of the (-)-enantiomer, solely due to a difference in their apparent Vmax values. 4. Sulphation of racemic prenalterol, a structural analogue of terbutaline, also showed a two-fold preference for the (+)-enantiomer. 5. These findings suggest that enantioselective sulphate conjugation of chiral phenolic sympathomimetic amine drugs may lead to enantioselective pharmacokinetics that should be considered in the clinical use of these drugs. PMID:2390423

  2. Reaction of aminals of conjugated omega-dimethylamino aldehydes with indandione

    SciTech Connect

    Krasnaya, Zh.A.; Stytsenko, T.S.; Gusev, D.G.; Prokof'ev, E.P.

    1987-01-20

    Conjugated omega-dimethylamino ..beta..-diketones with two to five double bonds and trimethylidyne- and pentamethylidyneoxanine salts are formed in the condensation of animals of conjugated ..beta..-dimethylamino aldehydes with indandione.

  3. Evaluation of Rhesus Monkey and Guinea Pig Hepatic Cytosol Fractions as Models for Human Aldehyde Oxidase

    PubMed Central

    Choughule, Kanika V.; Barr, John T.

    2013-01-01

    Aldehyde oxidase (AOX) is a cytosolic enzyme expressed across a wide range of species, including guinea pig and rhesus monkey. These species are believed to be the best preclinical models for studying human AOX-mediated metabolism. We compared AOX activity in rhesus monkeys, guinea pigs, and humans using phthalazine and N-[2-(dimethylamino)ethyl]acridone-4-carboxamide (DACA) as substrates and raloxifene as an inhibitor. Michaelis-Menten kinetics was observed for phthalazine oxidation in rhesus monkey, guinea pig, and human liver cytosol, whereas substrate inhibition was seen with DACA oxidase activity in all three livers. Raloxifene inhibited phthalazine and DACA oxidase activity uncompetitively in guinea pig, whereas mixed-mode inhibition was seen in rhesus monkey. Our analysis of the primary sequence alignment of rhesus monkey, guinea pig, and human aldehyde oxidase isoform 1 (AOX1) along with homology modeling has led to the identification of several amino acid residue differences within the active site and substrate entrance channel of AOX1. We speculate that some of these residues might be responsible for the differences observed in activity. Overall, our data indicate that rhesus monkeys and guinea pigs would overestimate intrinsic clearance in humans and would be unsuitable to use as animal models. Our study also showed that AOX metabolism in species is substrate-dependent and no single animal model can be reliably used to predict every drug response in humans. PMID:23918666

  4. Inactivation of cytosolic aldehyde dehydrogenase via-nitrosylation in ethanol-exposed rat liver

    PubMed Central

    Moon, Kwan-Hoon; Abdelmegeed, Mohamed A.; Song, Byoung-Joon

    2009-01-01

    Aldehyde dehydrogenase (ALDH) isozymes are critically important in the metabolism of acetaldehyde, thus preventing its accumulation after ethanol exposure. We previously reported that mitochondrial ALDH2 could be inactivated via -nitrosylation in ethanol-exposed rats. This study was aimed at investigating whether cytosolic ALDH1, with a relatively low- value (11–18 μM) for acetaldehyde, could be also inhibited in ethanol-exposed rats. Chronic or binge ethanol exposure significantly decreased ALDH1 activity, which was restored by addition of dithiothreitol. Immunoblot analysis with the anti--nitroso-Cys antibody showed one immunoreactive band in the immunoprecipiated ALDH1 only from ethanol-exposed rats, but not from pair-fed controls, suggesting -nitrosylation of ALDH1. Therefore inactivation of ALDH1 via -nitrosylation can result in accumulation of acetaldehyde upon ethanol exposure. PMID:17673211

  5. DABO Boronate Promoted Conjugate Allylation of α,β-Unsaturated Aldehydes Using Copper(II) Catalysis.

    PubMed

    Roest, Pjotr C; Michel, Nicholas W M; Batey, Robert A

    2016-08-01

    The first catalytic method for the selective 1,4-conjugate allylation of α,β-unsaturated aldehydes is reported. The method employs an air-stable diethanolamine-complexed boronic acid (DABO boronate) as the allyl transfer reagent and promotes conjugate addition over 1,2-addition. A variety of aryl- and alkyl-substituted enals are tolerated, providing δ,ε-unsaturated aldehyde products in good yields and selectivities under mild conditions. PMID:27362535

  6. Generation of thiols by biotransformation of cysteine-aldehyde conjugates with baker's yeast.

    PubMed

    Huynh-Ba, Tuong; Matthey-Doret, Walter; Fay, Laurent B; Bel Rhlid, Rachid

    2003-06-01

    Baker's yeast was shown to catalyze the transformation of cysteine-furfural conjugate into 2-furfurylthiol. The biotransformation's yield and kinetics were influenced by the reaction parameters such as pH, incubation mode (aerobic and anaerobic), and substrate concentration. 2-Furfurylthiol was obtained in an optimal 37% yield when cysteine-furfural conjugate at a 20 mM concentration was anaerobically incubated with whole cell baker's yeast at pH 8.0 and 30 degrees C. Similarly to 2-furfurylthiol, 5-methyl-2-furfurylthiol (11%), benzylthiol (8%), 2-thiophenemethanethiol (22%), 3-methyl-2-thiophenemethanethiol (3%), and 2-pyrrolemethanethiol (6%) were obtained from the corresponding cysteine-aldehyde conjugates by incubation with baker's yeast. This work indicates the versatile bioconversion capacity of baker's yeast for the generation of thiols from cysteine-aldehyde conjugates. Thanks to its food-grade character, baker's yeast provides a biochemical tool to produce thiols, which can be used as flavorings in foods and beverages.

  7. Efficient cytosolic delivery of molecular beacon conjugates and flow cytometric analysis of target RNA.

    PubMed

    Chen, Antony K; Behlke, Mark A; Tsourkas, Andrew

    2008-07-01

    Fluorescent microscopy experiments show that when 2'-O-methyl-modified molecular beacons (MBs) are introduced into NIH/3T3 cells, they elicit a nonspecific signal in the nucleus. This false-positive signal can be avoided by conjugating MBs to macromolecules (e.g. NeutrAvidin) that prevent nuclear sequestration, but the presence of a macromolecule makes efficient cytosolic delivery of these probes challenging. In this study, we explored various methods including TAT peptide, Streptolysin O and microporation for delivering NeutrAvidin-conjugates into the cytosol of living cells. Surprisingly, all of these strategies led to entrapment of the conjugates within lysosomes within 24 h. When the conjugates were pegylated, to help prevent intracellular recognition, only microporation led to a uniform cytosolic distribution. Microporation also yielded a transfection efficiency of 93% and an average viability of 86%. When cells microporated with MB-NeutrAvidin conjugates were examined via flow cytometry, the signal-to-background was found to be more than 3 times higher and the sensitivity nearly five times higher than unconjugated MBs. Overall, the present study introduces an improved methodology for the high-throughput detection of RNA at the single cell level.

  8. Peptide-Catalyzed Stereoselective Conjugate Addition Reactions of Aldehydes to Maleimide.

    PubMed

    Grünenfelder, Claudio E; Kisunzu, Jessica K; Wennemers, Helma

    2016-07-18

    The tripeptide H-dPro-Pro-Asn-NH2 is presented as a catalyst for asymmetric conjugate addition reactions of aldehydes to maleimide. The peptidic catalyst promotes the reaction between various aldehydes and unprotected maleimide with high stereoselectivities and yields. The obtained products were readily derivatized to the corresponding pyrrolidines, lactams, lactones, and peptide-like compounds. (1) H NMR spectroscopic, crystallographic, and computational investigations provided insight into the conformational properties of H-dPro-Pro-Asn-NH2 and revealed the importance of hydrogen bonding between the peptide and maleimide for catalyzing the stereoselective C-C bond formation.

  9. Mitochondrial Aldehyde Dehydrogenase 2 Plays Protective Roles in Heart Failure After Myocardial Infarction via Suppression of the Cytosolic JNK/p53 Pathway in Mice

    PubMed Central

    Sun, Aijun; Zou, Yunzeng; Wang, Ping; Xu, Danling; Gong, Hui; Wang, Shijun; Qin, Yingjie; Zhang, Peng; Chen, Yunqin; Harada, Mutsuo; Isse, Toyoshi; Kawamoto, Toshihiro; Fan, Huizhi; Yang, Pengyuan; Akazawa, Hiroshi; Nagai, Toshio; Takano, Hiroyuki; Ping, Peipei; Komuro, Issei; Ge, Junbo

    2014-01-01

    Background Increasing evidence suggests a critical role for mitochondrial aldehyde dehydrogenase 2 (ALDH2) in protection against cardiac injuries; however, the downstream cytosolic actions of this enzyme are largely undefined. Methods and Results Proteomic analysis identified a significant downregulation of mitochondrial ALDH2 in the heart of a rat heart failure model after myocardial infarction. The mechanistic insights underlying ALDH2 action were elucidated using murine models overexpressing ALDH2 or its mutant or with the ablation of the ALDH2 gene (ALDH2 knockout) and neonatal cardiomyocytes undergoing altered expression and activity of ALDH2. Left ventricle dilation and dysfunction and cardiomyocyte death after myocardial infarction were exacerbated in ALDH2‐knockout or ALDH2 mutant‐overexpressing mice but were significantly attenuated in ALDH2‐overexpressing mice. Using an anoxia model of cardiomyocytes with deficiency in ALDH2 activities, we observed prominent cardiomyocyte apoptosis and increased accumulation of the reactive aldehyde 4‐hydroxy‐2‐nonenal (4‐HNE). We subsequently examined the impacts of mitochondrial ALDH2 and 4‐HNE on the relevant cytosolic protective pathways. Our data documented 4‐HNE‐stimulated p53 upregulation via the phosphorylation of JNK, accompanying increased cardiomyocyte apoptosis that was attenuated by inhibition of p53. Importantly, elevation of 4‐HNE also triggered a reduction of the cytosolic HSP70, further corroborating cytosolic action of the 4‐HNE instigated by downregulation of mitochondrial ALDH2. Conclusions Downregulation of ALDH2 in the mitochondria induced an elevation of 4‐HNE, leading to cardiomyocyte apoptosis by subsequent inhibition of HSP70, phosphorylation of JNK, and activation of p53. This chain of molecular events took place in both the mitochondria and the cytosol, contributing to the mechanism underlying heart failure. PMID:25237043

  10. Aldehyde tag coupled with HIPS chemistry enables the production of ADCs conjugated site-specifically to different antibody regions with distinct in vivo efficacy and PK outcomes.

    PubMed

    Drake, Penelope M; Albers, Aaron E; Baker, Jeanne; Banas, Stefanie; Barfield, Robyn M; Bhat, Abhijit S; de Hart, Gregory W; Garofalo, Albert W; Holder, Patrick; Jones, Lesley C; Kudirka, Romas; McFarland, Jesse; Zmolek, Wes; Rabuka, David

    2014-07-16

    It is becoming increasingly clear that site-specific conjugation offers significant advantages over conventional conjugation chemistries used to make antibody-drug conjugates (ADCs). Site-specific payload placement allows for control over both the drug-to-antibody ratio (DAR) and the conjugation site, both of which play an important role in governing the pharmacokinetics (PK), disposition, and efficacy of the ADC. In addition to the DAR and site of conjugation, linker composition also plays an important role in the properties of an ADC. We have previously reported a novel site-specific conjugation platform comprising linker payloads designed to selectively react with site-specifically engineered aldehyde tags on an antibody backbone. This chemistry results in a stable C-C bond between the antibody and the cytotoxin payload, providing a uniquely stable connection with respect to the other linker chemistries used to generate ADCs. The flexibility and versatility of the aldehyde tag conjugation platform has enabled us to undertake a systematic evaluation of the impact of conjugation site and linker composition on ADC properties. Here, we describe the production and characterization of a panel of ADCs bearing the aldehyde tag at different locations on an IgG1 backbone conjugated using Hydrazino-iso-Pictet-Spengler (HIPS) chemistry. We demonstrate that in a panel of ADCs with aldehyde tags at different locations, the site of conjugation has a dramatic impact on in vivo efficacy and pharmacokinetic behavior in rodents; this advantage translates to an improved safety profile in rats as compared to a conventional lysine conjugate. PMID:24924618

  11. Adapting to substrate challenges: peptides as catalysts for conjugate addition reactions of aldehydes to α,β-disubstituted nitroolefins.

    PubMed

    Duschmalé, Jörg; Wennemers, Helma

    2012-01-23

    Conjugate addition reactions of aldehydes to α,β-disubstituted nitroolefins are important because they provide synthetically useful γ-nitroaldehydes bearing three consecutive stereogenic centers. Such reactions are challenging due to the drastically lower reactivity of α,β-disubstituted nitroolefins compared to, for example, β-monosubstituted nitroolefins. The testing of a small collection of peptides of the type Pro-Pro-Xaa (Xaa=acidic amino acid) led to the identification of H-Pro-Pro-D-Gln-OH and H-Pro-Pro-Asn-OH as excellent stereoselective catalysts for this transformation. In the presence of 5 mol% of these peptides different combinations of aldehydes and α,β-disubstituted nitroolefins react readily with each other providing γ-nitroaldehydes in good yields and diastereoselectivities as well as excellent enantioselectivities. Chiral pyrrolidines as well as fully substituted γ-butyrolactams and γ-amino acids are easily accessible from the γ-nitroaldehydes. Mechanistic studies demonstrate that the configuration at all three stereogenic centers is induced by the peptidic catalysts. Only a minimal amount of products from homo-aldol reactions is observed demonstrating the high chemoselectivity of the peptidic catalysts.

  12. Detection of aldehydes and their conjugated hydroperoxydiene precursors in thermally-stressed culinary oils and fats: investigations using high resolution proton NMR spectroscopy.

    PubMed

    Haywood, R M; Claxson, A W; Hawkes, G E; Richardson, D P; Naughton, D P; Coumbarides, G; Hawkes, J; Lynch, E J; Grootveld, M C

    1995-05-01

    High field (400 and 600 MHz) proton NMR spectroscopy has been employed to investigate the thermally-induced autoxidation of glycerol-bound polyunsaturated fatty acids present in intact culinary frying oils and fats. Heating of these materials at 180 degrees C for periods of 30, 60 and 90 min. generated a variety of peroxidation products, notably aldehydes (alkanals, trans-2-alkenals and alka-2,4-dienals) and their conjugated hydroperoxydiene precursors. Since such aldehydes appear to be absorbed into the systemic circulation from the gut in vivo, the toxicological significance of their production during standard frying practices is discussed.

  13. Microsphere coated substrate containing reactive aldehyde groups

    NASA Technical Reports Server (NTRS)

    Rembaum, Alan (Inventor); Yen, Richard C. K. (Inventor)

    1984-01-01

    A synthetic organic resin is coated with a continuous layer of contiguous, tangential, individual microspheres having a uniform diameter preferably between 100 Angstroms and 2000 Angstroms. The microspheres are an addition polymerized polymer of an unsaturated aldehyde containing 4 to 20 carbon atoms and are covalently bonded to the substrate by means of high energy radiation grafting. The microspheres contain reactive aldehyde groups and can form conjugates with proteins such as enzymes or other aldehyde reactive materials.

  14. Metal-free catalytic enantioselective C-B bond formation: (pinacolato)boron conjugate additions to α,β-unsaturated ketones, esters, Weinreb amides, and aldehydes promoted by chiral N-heterocyclic carbenes.

    PubMed

    Wu, Hao; Radomkit, Suttipol; O'Brien, Jeannette M; Hoveyda, Amir H

    2012-05-16

    The first broadly applicable metal-free enantioselective method for boron conjugate addition (BCA) to α,β-unsaturated carbonyls is presented. The C-B bond forming reactions are promoted in the presence of 2.5-7.5 mol % of a readily accessible C(1)-symmetric chiral imidazolinium salt, which is converted, in situ, to the catalytically active diastereo- and enantiomerically pure N-heterocyclic carbene (NHC) by the common organic base 1,8-diazabicyclo[5.4.0]undec-7-ene (dbu). In addition to the commercially available bis(pinacolato)diboron [B(2)(pin)(2)], and in contrast to reactions with the less sterically demanding achiral NHCs, the presence of MeOH is required for high efficiency. Acyclic and cyclic α,β-unsaturated ketones, as well as acyclic esters, Weinreb amides, and aldehydes, can serve as suitable substrates; the desired β-boryl carbonyls are isolated in up to 94% yield and >98:2 enantiomer ratio (er). Transformations are often carried out at ambient temperature. In certain cases, such as when the relatively less reactive unsaturated amides are used, elevated temperatures are required (50-66 °C); nonetheless, reactions remain highly enantioselective. The utility of the NHC-catalyzed method is demonstrated through comparison with the alternative Cu-catalyzed protocols; in cases involving a polyfunctional substrate, unique profiles in chemoselectivity are exhibited by the metal-free approach (e.g., conjugate addition vs reaction with an alkyne, allene, or aldehyde). PMID:22559866

  15. Conjugation of 4-hydroxynonenal by largemouth bass (Micropterus salmoides) glutathione S-transferases.

    PubMed

    Pham, Robert T; Gardner, James L; Gallagher, Evan P

    2002-01-01

    The glutathione S-transferases (GST) are a major group of conjugative enzymes involved in the detoxification of electrophilic compounds and products of oxidative stress. We have previously described the kinetics of hepatic GST conjugation in largemouth bass using a variety of synthetic GST reference substrates. In the present study, we investigated the ability of largemouth bass hepatic GSTs to conjugate 4-hydroxynon-2-enal (4HNE), a mutagenic and cytotoxic alpha-beta-unsaturated aldehyde produced during oxidative injury. Hepatic cytosolic fractions from largemouth bass rapidly catalyzed GSH-dependent 4HNE conjugation, with the rate of GST-4HNE conjugation in bass liver exceeding those of several other mammalian and aquatic species. No apparent sex-related differences in GST-4HNE activity were observed among adult bass. SDS-PAGE and Western blotting analysis of GSH affinity-purified bass liver cytosolic GST revealed the presence of two major GST subunits of approximately 30 and 27 KDa that exhibited slight cross-reactivity when probed with a rat alpha class GST antibody, but not to rat mu, pi or theta class GST. The rapid conjugation of 4HNE by hepatic GST suggests an important role for GSTs in protecting against peroxidation of polyunsaturated fatty acids in bass liver.

  16. Peptide-catalyzed 1,4-addition reactions of aldehydes to nitroolefins.

    PubMed

    Kastl, Robert; Arakawa, Yukihiro; Duschmalé, Jörg; Wiesner, Markus; Wennemers, Helma

    2013-01-01

    Conjugate addition reactions of aldehydes to nitroolefins provide synthetically useful gamma-nitroaldehydes. Here we summarize our research on peptide-catalyzed conjugate addition reactions of aldehydes to differently substituted nitroolefins. We show that peptides of the general type Pro-Pro-Xaa (Xaa = acidic amino acid) are not only highly active, robust and stereoselective catalysts but have also remarkable chemoselectivities.

  17. Deletion of GSTA4-4 results in increased mitochondrial post-translational modification of proteins by reactive aldehydes following chronic ethanol consumption in mice

    PubMed Central

    Shearn, Colin T.; Fritz, Kristofer S.; Shearn, Alisabeth H.; Saba, Laura M.; Mercer, Kelly E.; Engi, Bridgette; Galligan, James J.; Zimniak, Piotr; Orlicky, David J.; Ronis, Martin J.; Petersen, Dennis R.

    2015-01-01

    Chronic alcohol consumption induces hepatic oxidative stress resulting in production of highly reactive electrophilic α/β-unsaturated aldehydes that have the potential to modify proteins. A primary mechanism of reactive aldehyde detoxification by hepatocytes is through GSTA4-driven enzymatic conjugation with GSH. Given reports that oxidative stress initiates GSTA4 translocation to the mitochondria, we hypothesized that increased hepatocellular damage in ethanol (EtOH)-fed GSTA4−/− mice is due to enhanced mitochondrial protein modification by reactive aldehydes. Chronic ingestion of EtOH increased hepatic protein carbonylation in GSTA4−/− mice as evidenced by increased 4-HNE and MDA immunostaining in the hepatic periportal region. Using mass spectrometric analysis of biotin hydrazide conjugated carbonylated proteins, a total of 829 proteins were identified in microsomal, cytosolic and mitochondrial fractions. Of these, 417 were novel to EtOH models. Focusing on mitochondrial fractions, 1.61-fold more carbonylated proteins were identified in EtOH-fed GSTA4−/− mice compared to their respective WT mice ingesting EtOH. Bioinformatic KEGG pathway analysis of carbonylated proteins from the mitochondrial fractions revealed an increased propensity for modification of proteins regulating oxidative phosphorylation, glucose, fatty acid, glutathione and amino acid metabolic processes in GSTA4−/− mice. Additional analysis revealed sites of reactive aldehyde protein modification on 26 novel peptides/proteins isolated from either SV/GSTA4−/− PF or EtOH fed mice. Among the peptides/proteins identified, ACSL, ACOX2, MTP, and THIKB contribute to regulation of fatty acid metabolism and ARG1, ARLY, and OAT, which regulate nitrogen and ammonia metabolism having direct relevance to ethanol-induced liver injury. These data define a role for GSTA4-4 in buffering hepatic oxidative stress associated with chronic alcohol consumption and that this GST isoform plays an

  18. Molecular Mechanisms of Aldehyde Toxicity: A Chemical Perspective

    PubMed Central

    2015-01-01

    Aldehydes are electrophilic compounds to which humans are pervasively exposed. Despite a significant health risk due to exposure, the mechanisms of aldehyde toxicity are poorly understood. This ambiguity is likely due to the structural diversity of aldehyde derivatives and corresponding differences in chemical reactions and biological targets. To gain mechanistic insight, we have used parameters based on the hard and soft, acids and bases (HSAB) theory to profile the different aldehyde subclasses with respect to electronic character (softness, hardness), electrophilic reactivity (electrophilic index), and biological nucleophilic targets. Our analyses indicate that short chain aldehydes and longer chain saturated alkanals are hard electrophiles that cause toxicity by forming adducts with hard biological nucleophiles, e.g., primary nitrogen groups on lysine residues. In contrast, α,β-unsaturated carbonyl derivatives, alkenals, and the α-oxoaldehydes are soft electrophiles that preferentially react with soft nucleophilic thiolate groups on cysteine residues. The aldehydes can therefore be grouped into subclasses according to common electronic characteristics (softness/hardness) and molecular mechanisms of toxicity. As we will discuss, the toxic potencies of these subgroups are generally related to corresponding electrophilicities. For some aldehydes, however, predictions of toxicity based on electrophilicity are less accurate due to inherent physicochemical variables that limit target accessibility, e.g., steric hindrance and solubility. The unsaturated aldehydes are also members of the conjugated type-2 alkene chemical class that includes α,β-unsaturated amide, ketone, and ester derivatives. Type-2 alkenes are electrophiles of varying softness and electrophilicity that share a common mechanism of toxicity. Therefore, exposure to an environmental mixture of unsaturated carbonyl derivatives could cause “type-2 alkene toxicity” through additive interactions

  19. Molecular mechanisms of aldehyde toxicity: a chemical perspective.

    PubMed

    LoPachin, Richard M; Gavin, Terrence

    2014-07-21

    Aldehydes are electrophilic compounds to which humans are pervasively exposed. Despite a significant health risk due to exposure, the mechanisms of aldehyde toxicity are poorly understood. This ambiguity is likely due to the structural diversity of aldehyde derivatives and corresponding differences in chemical reactions and biological targets. To gain mechanistic insight, we have used parameters based on the hard and soft, acids and bases (HSAB) theory to profile the different aldehyde subclasses with respect to electronic character (softness, hardness), electrophilic reactivity (electrophilic index), and biological nucleophilic targets. Our analyses indicate that short chain aldehydes and longer chain saturated alkanals are hard electrophiles that cause toxicity by forming adducts with hard biological nucleophiles, e.g., primary nitrogen groups on lysine residues. In contrast, α,β-unsaturated carbonyl derivatives, alkenals, and the α-oxoaldehydes are soft electrophiles that preferentially react with soft nucleophilic thiolate groups on cysteine residues. The aldehydes can therefore be grouped into subclasses according to common electronic characteristics (softness/hardness) and molecular mechanisms of toxicity. As we will discuss, the toxic potencies of these subgroups are generally related to corresponding electrophilicities. For some aldehydes, however, predictions of toxicity based on electrophilicity are less accurate due to inherent physicochemical variables that limit target accessibility, e.g., steric hindrance and solubility. The unsaturated aldehydes are also members of the conjugated type-2 alkene chemical class that includes α,β-unsaturated amide, ketone, and ester derivatives. Type-2 alkenes are electrophiles of varying softness and electrophilicity that share a common mechanism of toxicity. Therefore, exposure to an environmental mixture of unsaturated carbonyl derivatives could cause "type-2 alkene toxicity" through additive interactions

  20. Microbial Engineering for Aldehyde Synthesis

    PubMed Central

    Kunjapur, Aditya M.

    2015-01-01

    Aldehydes are a class of chemicals with many industrial uses. Several aldehydes are responsible for flavors and fragrances present in plants, but aldehydes are not known to accumulate in most natural microorganisms. In many cases, microbial production of aldehydes presents an attractive alternative to extraction from plants or chemical synthesis. During the past 2 decades, a variety of aldehyde biosynthetic enzymes have undergone detailed characterization. Although metabolic pathways that result in alcohol synthesis via aldehyde intermediates were long known, only recent investigations in model microbes such as Escherichia coli have succeeded in minimizing the rapid endogenous conversion of aldehydes into their corresponding alcohols. Such efforts have provided a foundation for microbial aldehyde synthesis and broader utilization of aldehydes as intermediates for other synthetically challenging biochemical classes. However, aldehyde toxicity imposes a practical limit on achievable aldehyde titers and remains an issue of academic and commercial interest. In this minireview, we summarize published efforts of microbial engineering for aldehyde synthesis, with an emphasis on de novo synthesis, engineered aldehyde accumulation in E. coli, and the challenge of aldehyde toxicity. PMID:25576610

  1. Aldehyde-stabilized cryopreservation.

    PubMed

    McIntyre, Robert L; Fahy, Gregory M

    2015-12-01

    We describe here a new cryobiological and neurobiological technique, aldehyde-stabilized cryopreservation (ASC), which demonstrates the relevance and utility of advanced cryopreservation science for the neurobiological research community. ASC is a new brain-banking technique designed to facilitate neuroanatomic research such as connectomics research, and has the unique ability to combine stable long term ice-free sample storage with excellent anatomical resolution. To demonstrate the feasibility of ASC, we perfuse-fixed rabbit and pig brains with a glutaraldehyde-based fixative, then slowly perfused increasing concentrations of ethylene glycol over several hours in a manner similar to techniques used for whole organ cryopreservation. Once 65% w/v ethylene glycol was reached, we vitrified brains at -135 °C for indefinite long-term storage. Vitrified brains were rewarmed and the cryoprotectant removed either by perfusion or gradual diffusion from brain slices. We evaluated ASC-processed brains by electron microscopy of multiple regions across the whole brain and by Focused Ion Beam Milling and Scanning Electron Microscopy (FIB-SEM) imaging of selected brain volumes. Preservation was uniformly excellent: processes were easily traceable and synapses were crisp in both species. Aldehyde-stabilized cryopreservation has many advantages over other brain-banking techniques: chemicals are delivered via perfusion, which enables easy scaling to brains of any size; vitrification ensures that the ultrastructure of the brain will not degrade even over very long storage times; and the cryoprotectant can be removed, yielding a perfusable aldehyde-preserved brain which is suitable for a wide variety of brain assays. PMID:26408851

  2. Benzene toxicity: emphasis on cytosolic dihydrodiol dehydrogenases

    SciTech Connect

    Bolcsak, L.E.

    1982-01-01

    Blood dyscrasias such as leukopenia and anemia have been clearly identified as consequences of chronic benzene exposure. The metabolites, phenol, catechol, and hydroquinone produced inhibition of /sup 59/Fe uptake in mice which followed the same time course as that produced by benzene. The inhibitor of benzene oxidation, 3-amino-1,2,4-triazole, mitigated the inhibitory effects of benzene and phenol only. These data support the contention that benzene toxicity is mediated by a metabolite and suggest that the toxicity of phenol is a consequence of its metabolism to hydroquinone and that the route of metabolism to catechol may also contribute to the production of toxic metabolite(s). The properties of mouse liver cytosolic dihydrodiol dehydrogenases were examined. These enzymes catalyze the NADP/sup +/-dependent oxidation of trans-1,2-dihydro-1,2-dihydroxybenzene (BDD) to catechol, a possible toxic metabolite of benzene produced via this metabolic route. Four distinct dihydrodiol dehydrogenases (DD1, DD2, DD3, and DD4) were purified to apparent homogeneity as judged by SDS polyacrylamide gel electrophoresis and isoelectric focusing. DD1 appeared to be identical to the major ketone reductase and 17..beta..-hydroxysteroid dehydrogenase activity in the liver. DD2 exhibited aldehyde reductase activity. DD3 and DD4 oxidized 17..beta..-hydroxysteroids, but no carbonyl reductase activity was detected. These relationships between BDD dehydrogenases and carbonyl reductase and/or 17..beta..-hydroxysteroid dehydrogenase activities were supported by several lines of evidence.

  3. Alcohol, Aldehydes, Adducts and Airways.

    PubMed

    Sapkota, Muna; Wyatt, Todd A

    2015-11-05

    Drinking alcohol and smoking cigarettes results in the formation of reactive aldehydes in the lung, which are capable of forming adducts with several proteins and DNA. Acetaldehyde and malondialdehyde are the major aldehydes generated in high levels in the lung of subjects with alcohol use disorder who smoke cigarettes. In addition to the above aldehydes, several other aldehydes like 4-hydroxynonenal, formaldehyde and acrolein are also detected in the lung due to exposure to toxic gases, vapors and chemicals. These aldehydes react with nucleophilic targets in cells such as DNA, lipids and proteins to form both stable and unstable adducts. This adduction may disturb cellular functions as well as damage proteins, nucleic acids and lipids. Among several adducts formed in the lung, malondialdehyde DNA (MDA-DNA) adduct and hybrid malondialdehyde-acetaldehyde (MAA) protein adducts have been shown to initiate several pathological conditions in the lung. MDA-DNA adducts are pre-mutagenic in mammalian cells and induce frame shift and base-pair substitution mutations, whereas MAA protein adducts have been shown to induce inflammation and inhibit wound healing. This review provides an insight into different reactive aldehyde adducts and their role in the pathogenesis of lung disease.

  4. Alcohol, Aldehydes, Adducts and Airways.

    PubMed

    Sapkota, Muna; Wyatt, Todd A

    2015-01-01

    Drinking alcohol and smoking cigarettes results in the formation of reactive aldehydes in the lung, which are capable of forming adducts with several proteins and DNA. Acetaldehyde and malondialdehyde are the major aldehydes generated in high levels in the lung of subjects with alcohol use disorder who smoke cigarettes. In addition to the above aldehydes, several other aldehydes like 4-hydroxynonenal, formaldehyde and acrolein are also detected in the lung due to exposure to toxic gases, vapors and chemicals. These aldehydes react with nucleophilic targets in cells such as DNA, lipids and proteins to form both stable and unstable adducts. This adduction may disturb cellular functions as well as damage proteins, nucleic acids and lipids. Among several adducts formed in the lung, malondialdehyde DNA (MDA-DNA) adduct and hybrid malondialdehyde-acetaldehyde (MAA) protein adducts have been shown to initiate several pathological conditions in the lung. MDA-DNA adducts are pre-mutagenic in mammalian cells and induce frame shift and base-pair substitution mutations, whereas MAA protein adducts have been shown to induce inflammation and inhibit wound healing. This review provides an insight into different reactive aldehyde adducts and their role in the pathogenesis of lung disease. PMID:26556381

  5. Ubiquitin-aldehyde: a general inhibitor of ubiquitin-recycling processes.

    PubMed Central

    Hershko, A; Rose, I A

    1987-01-01

    The generation and characterization of ubiquitin (Ub)-aldehyde, a potent inhibitor of Ub-C-terminal hydrolase, has previously been reported. We now examine the action of this compound on the Ub-mediated proteolytic pathway using the system derived from rabbit reticulocytes. Addition of Ub-aldehyde was found to strongly inhibit breakdown of added 125I-labeled lysozyme, but inhibition was overcome by increasing concentrations of Ub. The following evidence shows the effect of Ub-aldehyde on protein breakdown to be indirectly caused by its interference with the recycling of Ub, leading to exhaustion of the supply of free Ub: Ub-aldehyde markedly increased the accumulation of Ub-protein conjugates coincident with a much decreased rate of conjugate breakdown. release of Ub from isolated Ub-protein conjugates in the absence of ATP (and therefore not coupled to protein degradation) is markedly inhibited by Ub-aldehyde. On the other hand, the ATP-dependent degradation of the protein moiety of Ub conjugates, which is an integral part of the proteolytic process, is not inhibited by this agent. Direct measurement of levels of free Ub showed a rapid disappearance caused by the inhibitor. The Ub is found to be distributed in derivatives of a wide range of molecular weight classes. It thus seems that Ub-aldehyde, previously demonstrated to inhibit the hydrolysis of Ub conjugates of small molecules, also inhibits the activity of a series of enzymes that regenerate free Ub from adducts with proteins and intermediates in protein breakdown. Images PMID:3031653

  6. Aldehyde dehydrogenase 7A1 (ALDH7A1) attenuates reactive aldehyde and oxidative stress induced cytotoxicity

    PubMed Central

    Brocker, Chad; Cantore, Miriam; Failli, Paola; Vasiliou, Vasilis

    2012-01-01

    Mammalian aldehyde dehydrogenase 7A1 (ALDH7A1) is homologous to plant ALDH7B1 which protects against various forms of stress such as increased salinity, dehydration and treatment with oxidants or pesticides. Deleterious mutations in human ALDH7A1 are responsible for pyridoxine-dependent and folinic acid-responsive seizures. In previous studies, we have shown that human ALDH7A1 protects against hyperosmotic stress presumably through the generation of betaine, an important cellular osmolyte, formed from betaine aldehyde. Hyperosmotic stress is coupled to an increase in oxidative stress and lipid peroxidation (LPO). In this study, cell viability assays revealed that stable expression of mitochondrial ALDH7A1 in Chinese hamster ovary (CHO) cells provides significant protection against treatment with the LPO-derived aldehydes hexanal and 4-hydroxy-2-nonenal (4HNE) implicating a protective function for the enzyme during oxidative stress. A significant increase in cell survival was also observed in CHO cells expressing either mitochondrial or cytosolic ALDH7A1 treated with increasing concentrations of hydrogen peroxide (H2O2) or 4HNE, providing further evidence for anti-oxidant activity. In vitro enzyme activity assays indicate that human ALDH7A1 is sensitive to oxidation and that efficiency can be at least partially restored by incubating recombinant protein with the thiol reducing agent β-mercaptoethanol (BME). We also show that after reactivation with BME, recombinant ALDH7A1 is capable of metabolizing the reactive aldehyde 4HNE. In conclusion, ALDH7A1 mechanistically appears to provide cells protection through multiple pathways including the removal of toxic LPO-derived aldehydes in addition to osmolyte generation. PMID:21338592

  7. Census of cytosolic aminopeptidase activity reveals two novel cytosolic aminopeptidases.

    PubMed

    Akkad, Nadja; Schatz, Mark; Dengjel, Jörn; Tenzer, Stefan; Schild, Hansjörg

    2012-11-01

    Activation of CD8(+) cytotoxic T cells is crucial for the adaptive immune response against viral infections and the control of malignant transformed cells. Together with activation of costimulatory molecules like CD3 and CD28, CD8(+) T cells need activation of their unique T cell receptor via recognition of foreign peptide epitopes in combination with major histocompatibility complexes class I on the cell surface of professional antigen-presenting cells. Presentation of pathogen-associated proteins is the result of a complex proteolytic process. It starts with the breakdown of proteins by a cytosolic endopeptidase, the proteasome, and is continued by subsequent N-terminal trimming events in the cytosol and/or the endoplasmic reticulum. Analysis of the proteolytic aminopeptidase activity in the former cellular compartment showed that the cytosol harbors a multitude of aminopeptidases that have singular specificities, but on the other hand also show redundancy in the trimming of N-terminal residues. The observed pattern of the overall trimming in the cytosol is reflected by the activity of the four identified aminopeptidases, and the administration of protease inhibitors made it possible to assign specificity of cleaving of proteinogenic amino acids to one or more identified aminopeptidase. The only exception was the cleavage of aspartic acid, which is performed by one yet unidentified enzyme.

  8. α,β-Unsaturated aldehyde of hyaluronan--Synthesis, analysis and applications.

    PubMed

    Buffa, Radovan; Šedová, Petra; Basarabová, Ivana; Moravcová, Martina; Wolfová, Lucie; Bobula, Tomáš; Velebný, Vladimír

    2015-12-10

    Hyaluronic acid (HA) modified with an aldehyde group (HA-CHO or HA-aldehyde) has been extensively used for various biomedical applications. The main advantage of the aldehyde moieties is the ability to react with a wide range of amino compounds under physiological conditions. Reactions of aldehydes with primary amines in water are reversible and equilibrium is thoroughly shifted towards starting aldehyde and amine. This work presents an unique modification of HA: α,β-unsaturated aldehyde of HA (4,5-anhydro-6(GlcNAc)-oxo HA or ΔHA-CHO), which allows the primary amines to be attached to HA more effectively in comparison to the saturated HA-CHO. Higher hydrolytic stability is caused by the conjugation of imine with an adjacent --C=C-- double bond. Two strategies for the preparation of unsaturated HA-aldehyde were developed and chemical structures were studied in details. Cross-linked materials prepared from this precursor are biocompatible and suitable for applications in drug delivery and regenerative medicine. PMID:26428127

  9. ALDEHYDE DEHYDROGENASES EXPRESSION DURING POSTNATAL DEVELOPMENT: LIVER VS. LUNG

    EPA Science Inventory

    Aldehydes are highly reactive molecules present in the environment, and can be produced during biotransformation of xenobiotics. Although the lung can be a major target for aldehyde toxicity, development of aldehyde dehydrogenases (ALDHs), which detoxify aldehydes, in lung has be...

  10. Synthesis of 5'-Aldehyde Oligonucleotide.

    PubMed

    Lartia, Rémy

    2016-01-01

    Synthesis of oligonucleotide ending with an aldehyde functional group at their 5'-end (5'-AON) is possible for both DNA (5'-AODN) and RNA (5'-AORN) series irrespectively of the nature of the last nucleobase. The 5'-alcohol of on-support ODN is mildly oxidized under Moffat conditions. Transient protection of the resulting aldehyde by N,N'-diphenylethylenediamine derivatives allows cleavage, deprotection, and RP-HPLC purification of the protected 5'-AON. Finally, 5'-AON is deprotected by usual acetic acid treatment. In the aggregates, 5'-AON can be now synthesized and purified as routinely as non-modified ODNs, following procedures similar to the well-known "DMT-On" strategy. PMID:26967469

  11. Immobilization of DNA via oligonucleotides containing an aldehyde or carboxylic acid group at the 5' terminus.

    PubMed Central

    Kremsky, J N; Wooters, J L; Dougherty, J P; Meyers, R E; Collins, M; Brown, E L

    1987-01-01

    A general method for the immobilization of DNA through its 5'-end has been developed. A synthetic oligonucleotide, modified at its 5'-end with an aldehyde or carboxylic acid, was attached to latex microspheres containing hydrazide residues. Using T4 polynucleotide ligase and an oligonucleotide splint, a single stranded 98mer was efficiently joined to the immobilized synthetic fragment. After impregnation of the latex microspheres with the fluorescent dye, Nile Red and attachment of an aldehyde 16mer, 5 X 10(5) bead-DNA conjugates could be detected with a conventional fluorimeter. Images PMID:3562241

  12. The Pivotal Role of Aldehyde Toxicity in Autism Spectrum Disorder: The Therapeutic Potential of Micronutrient Supplementation

    PubMed Central

    Jurnak, Frances

    2015-01-01

    Autism spectrum disorder (ASD) is characterized by social and communication impairments as well as by restricted, repetitive patterns of behavior and interests. Genomic studies have not revealed dominant genetic errors common to all forms of ASD. So ASD is assumed to be a complex disorder due to mutations in hundreds of common variants. Other theories argue that spontaneous DNA mutations and/or environmental factors contribute to as much as 50% of ASD. In reviewing potential genetic linkages between autism and alcoholism, it became apparent that all theories of ASD are consistent with aldehyde toxicity, in which endogenous and exogenous aldehydes accumulate as a consequence of mutations in key enzymes. Aldehyde toxicity is characterized by cell-localized, micronutrient deficiencies in sulfur-containing antioxidants, thiamine (B1), pyridoxine (B6), folate, Zn2+, possibly Mg2+, and retinoic acid, causing oxidative stress and a cascade of metabolic disturbances. Aldehydes also react with selective cytosolic and membrane proteins in the cell of origin; then some types migrate to damage neighboring cells. Reactive aldehydes also form adducts with DNA, selectively mutating bases and inducing strand breakage. This article reviews the relevant genomic, biochemical, and nutritional literature, which supports the central hypothesis that most ASD symptoms are consistent with symptoms of aldehyde toxicity. The hypothesis represents a paradigm shift in thinking and has profound implications for clinical detection, treatment, and even prevention of ASD. Insight is offered as to which neurologically afflicted children might successfully be treated with micronutrients and which children are unlikely to be helped. The aldehyde toxicity hypothesis likely applies to other neurological disorders. PMID:27330305

  13. Autoimmune Hepatitis Induced by Syngeneic Liver Cytosolic Proteins Biotransformed by Alcohol Metabolites

    PubMed Central

    Thiele, Geoffrey M.; Duryee, Michael J.; Willis, Monte S.; Tuma, Dean J.; Radio, Stanley J.; Hunter, Carlos D.; Schaffert, Courtney S.; Klassen, Lynell W.

    2010-01-01

    Background & Aims Aldehydes that are produced following the breakdown of ethanol (acetaldehyde) and lipid peroxidation of membranes (malondialdehyde) have been shown to bind (adduct) proteins. Additionally, these two aldehydes can combine (MAA) on non-syngeneic and syngeneic proteins to initiate numerous immune responses to the unmodified part of the protein in the absence of an adjuvant. Therefore, these studies provide a potential mechanism for the development of antigen-specific immune responses resulting in liver damage should syngeneic liver proteins be adducted with MAA. Methods This study sought to test whether MAA modified syngeneic liver cytosolic proteins administered daily in the absence of adjuvant into C57BL/6 mice abrogates tolerance to initiate a MAA induced autoimmune-like hepatitis (MIAH). Results In mice immunized with MAA modified cytosols there was an increase in liver damage as assessed by AST/ALT levels that correlated with liver pathology scores and the presence of the pro-fibrotic factors; smooth muscle actin (SMA), TGF-β, and collagen. IgG antibodies and T-cell proliferative responses specific for cytosolic proteins were also detected. Pro-inflammatory cytokines were produced in the livers of animals exposed to MAA-modified cytosols. Finally, transfer of immunized T-cells to naïve animals caused biochemical and histological evidence of liver damage. Conclusions These data demonstrate that a disease with an autoimmune-like pathophysiology can be generated in this animal model using soluble MAA modified syngeneic liver cytosols as the immunogen. These studies provide insight into potential mechanism(s) that the metabolites of alcohol may play in contributing to the onset of an autoimmune-like disease in ALD patients. PMID:20860619

  14. Detoxification of aldehydes by histidine-containing dipeptides: from chemistry to clinical implications

    PubMed Central

    Xie, Zhengzhi; Baba, Shahid P.; Sweeney, Brooke R.; Barski, Oleg A.

    2015-01-01

    Aldehydes are generated by oxidized lipids and carbohydrates at increased levels under conditions of metabolic imbalance and oxidative stress during atherosclerosis, myocardial and cerebral ischemia, diabetes, neurodegenerative diseases and trauma. In most tissues, aldehydes are detoxified by oxidoreductases that catalyze the oxidation or the reduction of aldehydes or enzymatic and nonenzymatic conjugation with low molecular weight thiols and amines, such as glutathione and histidine dipeptides. Histidine dipeptides are present in micromolar to millimolar range in the tissues of vertebrates, where they are involved in a variety of physiological functions such as pH buffering, metal chelation, oxidant and aldehyde scavenging. Histidine dipeptides such as carnosine form Michael adducts with lipid-derived unsaturated aldehydes, and react with carbohydrate-derived oxo- and hydroxy- aldehydes forming products of unknown structure. Although these peptides react with electrophilic molecules at lower rate than glutathione, they can protect glutathione from modification by oxidant and they may be important for aldehyde quenching in glutathione-depleted cells or extracellular space where glutathione is scarce. Consistent with in vitro findings, treatment with carnosine has been shown to diminish ischemic injury, improve glucose control, ameliorate the development of complications in animal models of diabetes and obesity, promote wound healing and decrease atherosclerosis. The protective effects of carnosine have been linked to its anti-oxidant properties, it ability to promote glycolysis, detoxify reactive aldehydes and enhance histamine levels. Thus, treatment with carnosine and related histidine dipeptides may be a promising strategy for the prevention and treatment of diseases associated with high carbonyl load. PMID:23313711

  15. Process for producing furan from furfural aldehyde

    DOEpatents

    Diebold, J.P.; Evans, R.J.

    1987-04-06

    A process of producing furan and derivatives thereof as disclosed. The process includes generating furfural aldehyde vapors and then passing those vapors over a zeolite catalyst at a temperature and for a residence time effective to decarbonylate the furfural aldehydes to form furans and derivatives thereof. The resultant furan vapors and derivatives are then separated. In a preferred form, the furfural aldehyde vapors are generated during the process of converting biomass materials to liquid and gaseous fuels.

  16. Process for producing furan from furfural aldehyde

    DOEpatents

    Diebold, James P.; Evans, Robert J.

    1988-01-01

    A process of producing furan and derivatives thereof is disclosed. The process includes generating furfural aldehyde vapors and then passing those vapors over a zeolite catalyst at a temperature and for a residence time effective to decarbonylate the furfural aldehydes to form furans and derivatives thereof. The resultant furan vapors and derivatives are then separated. In a preferred form, the furfural aldehyde vapors are generated during the process of converting biomass materials to liquid and gaseous fuels.

  17. DIFFERENTIATING THE TOXICITY OF CARCINOGENIC ALDEHYDES FROM NONCARCINOGENIC ALDEHYDES IN THE RAT NOSE USING CDNA ARRAYS

    EPA Science Inventory

    Differentiating the Toxicity of Carcinogenic Aldehydes from Noncarcinogenic Aldehydes in the Rat Nose Using cDNA Arrays.

    Formaldehyde is a widely used aldehyde in many industrial settings, the tanning process, household products, and is a contaminant in cigarette smoke. H...

  18. Life cycle of cytosolic prions.

    PubMed

    Hofmann, Julia; Vorberg, Ina

    2013-01-01

    Prions are self-templating protein aggregates that were originally identified as the causative agent of prion diseases in mammals, but have since been discovered in other kingdoms. Mammalian prions represent a unique class of infectious agents that are composed of misfolded prion protein. Prion proteins usually exist as soluble proteins but can refold and assemble into highly ordered, self-propagating prion polymers. The prion concept is also applicable to a growing number of non-Mendelian elements of inheritance in lower eukaryotes. While prions identified in mammals are clearly pathogens, prions in lower eukaryotes can be either detrimental or beneficial to the host. Prion phenotypes in fungi are transmitted vertically from mother to daughter cells during cell division and horizontally during mating or abortive mating, but extracellular phases have not been reported. Recent findings now demonstrate that in a mammalian cell environment, protein aggregates derived from yeast prion domains exhibit a prion life cycle similar to mammalian prions propagated ex vivo. This life cycle includes a soluble state of the protein, an induction phase by exogenous prion fibrils, stable replication of prion entities, vertical transmission to progeny and natural horizontal transmission to neighboring cells. Our data reveal that mammalian cells contain all co-factors required for cytosolic prion propagation and dissemination. This has important implications for understanding prion-like properties of disease-related protein aggregates. In light of the growing number of identified functional amyloids, cell-to-cell propagation of cytosolic protein conformers might not only be relevant for the spreading of disease-associated proteins, but might also be of more general relevance under non-disease conditions.

  19. Gaseous aliphatic aldehydes in Chinese incense smoke

    SciTech Connect

    Lin, J.M.; Wang, L.H. )

    1994-09-01

    Aliphatic aldehydes were found during the combustion of materials. Tobacco smoke contains aldehydes. Fire fighters were exposed to aldehydes when they conducted firefighting. Aldehydes in ambient air come mainly from the incomplete combustion of hydrocarbons and from photochemical reaction. Most aldehydes in ambient air are formaldehyde and acetaldehyde. Formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, and benzaldehyde were found in the atmosphere in Los Angeles. Burning Chinese incense for worshipping deities is a Chinese daily routine. It was suspected to be a factor causing nasopharynegeal cancer. Epidemiological studies correlated it with the high risk of childhood brain tumor and the high risk of childhood leukemia. Ames test identified the mutagenic effect of the smoke from burning Chinese incense. The smoke had bee proved to contain polycyclic aromatic hydrocarbons and aromatic aldehydes. Suspicion about formaldehyde and other alphatic aldehydes was evoked, when a survey of indoor air pollution was conducted in Taipei city. This study determined the presence of aliphatic aldehydes in the smoke from burning Chinese incense under a controlled atmosphere. 12 refs., 5 figs., 2 tabs.

  20. Aldehyde-containing urea-absorbing polysaccharides

    NASA Technical Reports Server (NTRS)

    Mueller, W. A.; Hsu, G. C.; Marsh, H. E., Jr. (Inventor)

    1977-01-01

    A novel aldehyde containing polymer (ACP) is prepared by reaction of a polysaccharide with periodate to introduce aldehyde groups onto the C2 - C3 carbon atoms. By introduction of ether and ester groups onto the pendant primary hydroxyl solubility characteristics are modified. The ACP is utilized to absorb nitrogen bases such as urea in vitro or in vivo.

  1. EMISSIONS OF ODOROUS ALDEHYDES FROM ALKYD PAINT

    EPA Science Inventory

    Aldehyde emissions are widely held responsible for the acrid after-odor of drying alkyd-based paint films. The aldehyde emissions from three different alkyd paints were measured in small environmental chambers. It was found that, for each alkyd paint applied, more than 2 mg of ...

  2. Emissions of odorous aldehydes from alkyd paint

    NASA Astrophysics Data System (ADS)

    Chang, John C. S.; Guo, Zhishi

    Aldehyde emissions are widely held responsible for the acrid after-odor of drying alkyd-based paint films. The aldehyde emissions from three different alkyd paints were measured in small environ-mental chambers. It was found that, for each gram of alkyd paint applied, more than 2 mg of aldehydes (mainly hexanal) were emitted during the curing (drying) period. Since no measurable hexanal was found in the original paint, it is suspected that the aldehydes emitted were produced by autoxidation of the unsaturated fatty acid esters in the alkyd resins. The hexanal emission rate was simulated by a model assuming that the autoxidation process was controlled by a consecutive first-order reaction mechanism. Using the emission rate model, indoor air quality simulation indicated that the hexanal emissions can result in prolonged (several days) exposure risk to occupants. The occupant exposure to aldehydes emitted from alkyd paint also could cause sensory irritation and other health concerns.

  3. Retrograde transport is not required for cytosolic translocation of the B-subunit of Shiga toxin.

    PubMed

    Garcia-Castillo, Maria Daniela; Tran, Thi; Bobard, Alexandre; Renard, Henri-François; Rathjen, Stefan J; Dransart, Estelle; Stechmann, Bahne; Lamaze, Christophe; Lord, Mike; Cintrat, Jean-Christophe; Enninga, Jost; Tartour, Eric; Johannes, Ludger

    2015-07-01

    Antigen-presenting cells have the remarkable capacity to transfer exogenous antigens to the cytosol for processing by proteasomes and subsequent presentation on major histocompatibility complex class-I (MHC-I) molecules, a process termed cross-presentation. This is the target of biomedical approaches that aim to trigger a therapeutic immune response. The receptor-binding B-subunit of Shiga toxin (STxB) has been developed as an antigen delivery tool for such immunotherapy applications. In this study, we have analyzed pathways and trafficking factors that are involved in this process. A covalent conjugate between STxB and saporin was generated to quantitatively sample the membrane translocation step to the cytosol in differentiated monocyte-derived THP-1 cells. We have found that retrograde trafficking to the Golgi complex was not required for STxB-saporin translocation to the cytosol or for STxB-dependent antigen cross-presentation. Depletion of endosomal Rab7 inhibited, and lowering membrane cholesterol levels favored STxB-saporin translocation. Interestingly, experiments with reducible and non-reducible linker-arm-STxB conjugates led to the conclusion that after translocation, STxB remains associated with the cytosolic membrane leaflet. In summary, we report new facets of the endosomal escape process bearing relevance to antigen cross-presentation.

  4. Retrograde transport is not required for cytosolic translocation of the B-subunit of Shiga toxin.

    PubMed

    Garcia-Castillo, Maria Daniela; Tran, Thi; Bobard, Alexandre; Renard, Henri-François; Rathjen, Stefan J; Dransart, Estelle; Stechmann, Bahne; Lamaze, Christophe; Lord, Mike; Cintrat, Jean-Christophe; Enninga, Jost; Tartour, Eric; Johannes, Ludger

    2015-07-01

    Antigen-presenting cells have the remarkable capacity to transfer exogenous antigens to the cytosol for processing by proteasomes and subsequent presentation on major histocompatibility complex class-I (MHC-I) molecules, a process termed cross-presentation. This is the target of biomedical approaches that aim to trigger a therapeutic immune response. The receptor-binding B-subunit of Shiga toxin (STxB) has been developed as an antigen delivery tool for such immunotherapy applications. In this study, we have analyzed pathways and trafficking factors that are involved in this process. A covalent conjugate between STxB and saporin was generated to quantitatively sample the membrane translocation step to the cytosol in differentiated monocyte-derived THP-1 cells. We have found that retrograde trafficking to the Golgi complex was not required for STxB-saporin translocation to the cytosol or for STxB-dependent antigen cross-presentation. Depletion of endosomal Rab7 inhibited, and lowering membrane cholesterol levels favored STxB-saporin translocation. Interestingly, experiments with reducible and non-reducible linker-arm-STxB conjugates led to the conclusion that after translocation, STxB remains associated with the cytosolic membrane leaflet. In summary, we report new facets of the endosomal escape process bearing relevance to antigen cross-presentation. PMID:25977475

  5. Toward aldehyde and alkane production by removing aldehyde reductase activity in Escherichia coli

    PubMed Central

    Rodriguez, Gabriel M.; Atsumi, Shota

    2015-01-01

    Advances in synthetic biology and metabolic engineering have enabled the construction of novel biological routes to valuable chemicals using suitable microbial hosts. Aldehydes serve as chemical feedstocks in the synthesis of rubbers, plastics, and other larger molecules. Microbial production of alkanes is dependent on the formation of a fatty aldehyde intermediate which is converted to an alkane by an aldehyde deformylating oxygenase (ADO). However, microbial hosts such as Escherichia coli are plagued by many highly active endogenous aldehyde reductases (ALRs) that convert aldehydes to alcohols, which greatly complicates strain engineering for aldehyde and alkane production. It has been shown that the endogenous ALR activity outcompetes the ADO enzyme for fatty aldehyde substrate. The large degree of ALR redundancy coupled with an incomplete database of ALRs represents a significant obstacle in engineering E. coli for either aldehyde or alkane production. In this study, we identified 44 ALR candidates encoded in the E. coli genome using bioinformatics tools, and undertook a comprehensive screening by measuring the ability of these enzymes to produce isobutanol. From the pool of 44 candidates, we found five new ALRs using this screening method (YahK, DkgA, GldA, YbbO, and YghA). Combined deletions of all 13 known ALRs resulted in a 90–99% reduction in endogenous ALR activity for a wide range of aldehyde substrates (C2–C12). Elucidation of the ALRs found in E. coli could guide one in reducing competing alcohol formation during alkane or aldehyde production. PMID:25108218

  6. Methods to Design and Synthesize Antibody-Drug Conjugates (ADCs)

    PubMed Central

    Yao, Houzong; Jiang, Feng; Lu, Aiping; Zhang, Ge

    2016-01-01

    Antibody-drug conjugates (ADCs) have become a promising targeted therapy strategy that combines the specificity, favorable pharmacokinetics and biodistributions of antibodies with the destructive potential of highly potent drugs. One of the biggest challenges in the development of ADCs is the application of suitable linkers for conjugating drugs to antibodies. Recently, the design and synthesis of linkers are making great progress. In this review, we present the methods that are currently used to synthesize antibody-drug conjugates by using thiols, amines, alcohols, aldehydes and azides. PMID:26848651

  7. Detection of cytosolic bacteria by inflammatory caspases.

    PubMed

    Hagar, Jon A; Miao, Edward A

    2014-02-01

    The sanctity of the cytosolic compartment is rigorously maintained by a number of innate immune mechanisms. Inflammasomes detect signatures of microbial infection and trigger caspase-1 or caspase-11 activation, culminating in cytokine secretion and obliteration of the replicative niche via pyroptosis. Recent studies have examined inflammatory caspase responses to cytosolic bacteria, including Burkholderia, Shigella, Listeria, Francisella, and Mycobacterium species. For example, caspase-11 responds to LPS introduced into the cytosol after Gram-negative bacteria escape the vacuole. Not surprisingly, bacteria antagonize these responses; for example, Shigella delivers OspC3 to inhibit caspase-4, a potential human homolog of murine caspase-11. These findings underscore bacterial coevolution with the innate immune system, which has resulted in few, but highly specialized cytosolic pathogens.

  8. Detection of cytosolic bacteria by inflammatory caspases

    PubMed Central

    Hagar, Jon A.; Miao, Edward A.

    2014-01-01

    The sanctity of the cytosolic compartment is rigorously maintained by a number of innate immune mechanisms. Inflammasomes detect signatures of microbial infection and trigger caspase-1 or caspase-11 activation, culminating in cytokine secretion and obliteration of the replicative niche via pyroptosis. Recent studies have examined inflammatory caspase responses to cytosolic bacteria, including Burkholderia, Shigella, Listeria, Francisella, and Mycobacterium species. For example, caspase-11 responds to LPS introduced into the cytosol after Gram-negative bacteria escape the vacuole. Not surprisingly, bacteria antagonize these responses; for example, Shigella delivers OspC3 to inhibit caspase-4. These findings underscore bacterial coevolution with the innate immune system, which has resulted in few, but highly specialized cytosolic pathogens. PMID:24581694

  9. Mitochondrial aldehyde dehydrogenase and cardiac diseases

    PubMed Central

    Chen, Che-Hong; Sun, Lihan; Mochly-Rosen, Daria

    2010-01-01

    Numerous conditions promote oxidative stress, leading to the build-up of reactive aldehydes that cause cell damage and contribute to cardiac diseases. Aldehyde dehydrogenases (ALDHs) are important enzymes that eliminate toxic aldehydes by catalysing their oxidation to non-reactive acids. The review will discuss evidence indicating a role for a specific ALDH enzyme, the mitochondrial ALDH2, in combating oxidative stress by reducing the cellular ‘aldehydic load’. Epidemiological studies in humans carrying an inactive ALDH2, genetic models in mice with altered ALDH2 levels, and small molecule activators of ALDH2 all highlight the role of ALDH2 in cardioprotection and suggest a promising new direction in cardiovascular research and the development of new treatments for cardiovascular diseases. PMID:20558439

  10. Role and structural characterization of plant aldehyde dehydrogenases from family 2 and family 7.

    PubMed

    Končitíková, Radka; Vigouroux, Armelle; Kopečná, Martina; Andree, Tomáš; Bartoš, Jan; Šebela, Marek; Moréra, Solange; Kopečný, David

    2015-05-15

    Aldehyde dehydrogenases (ALDHs) are responsible for oxidation of biogenic aldehyde intermediates as well as for cell detoxification of aldehydes generated during lipid peroxidation. So far, 13 ALDH families have been described in plants. In the present study, we provide a detailed biochemical characterization of plant ALDH2 and ALDH7 families by analysing maize and pea ALDH7 (ZmALDH7 and PsALDH7) and four maize cytosolic ALDH(cALDH)2 isoforms RF2C, RF2D, RF2E and RF2F [the first maize ALDH2 was discovered as a fertility restorer (RF2A)]. We report the crystal structures of ZmALDH7, RF2C and RF2F at high resolution. The ZmALDH7 structure shows that the three conserved residues Glu(120), Arg(300) and Thr(302) in the ALDH7 family are located in the substrate-binding site and are specific to this family. Our kinetic analysis demonstrates that α-aminoadipic semialdehyde, a lysine catabolism intermediate, is the preferred substrate for plant ALDH7. In contrast, aromatic aldehydes including benzaldehyde, anisaldehyde, cinnamaldehyde, coniferaldehyde and sinapaldehyde are the best substrates for cALDH2. In line with these results, the crystal structures of RF2C and RF2F reveal that their substrate-binding sites are similar and are formed by an aromatic cluster mainly composed of phenylalanine residues and several nonpolar residues. Gene expression studies indicate that the RF2C gene, which is strongly expressed in all organs, appears essential, suggesting that the crucial role of the enzyme would certainly be linked to the cell wall formation using aldehydes from phenylpropanoid pathway as substrates. Finally, plant ALDH7 may significantly contribute to osmoprotection because it oxidizes several aminoaldehydes leading to products known as osmolytes. PMID:25734422

  11. Scavenger receptor for aldehyde-modified proteins.

    PubMed

    Horiuchi, S; Murakami, M; Takata, K; Morino, Y

    1986-04-15

    This paper describes an unexpectedly broad ligand specificity of a scavenger receptor of sinusoidal liver cells that is responsible for endocytic uptake of formaldehyde-treated bovine serum albumin (f-Alb). Binding of 125I-f-Alb to the isolated cells was effectively inhibited by bovine serum albumin (BSA) modified with aliphatic aldehydes such as glycolaldehye, DL-glyceraldehyde, and propionaldehyde whereas albumin preparations modified by aromatic aldehydes such as pyridoxal, pyridoxal phosphate, salicylaldehyde, and benzaldehyde did not affect this binding process. Binding of 125I-glycolaldehyde-treated BSA to the cells exhibited a saturation kinetics with an apparent Kd = 3.3 micrograms of the ligand/ml. This binding process was inhibited by unlabeled f-Alb as well as by the antibody raised against the f-Alb receptor. Indeed, 125I-glycolaldehyde-treated BSA underwent a rapid plasma clearance (t1/2 approximately 2 min) which was markedly retarded by unlabeled f-Alb. Upon treatment by these aldehydes, other proteins such as ovalbumin, soybean trypsin inhibitor, and hemoglobin were also converted to active ligands for the f-Alb receptor, while no ligand activity was generated with gamma-globulin and RNase A. These results clearly show that the f-Alb receptor, originally described as being specific for f-Alb, exhibits a broad ligand specificity in terms of both aldehydes and proteins and, hence, should be described as a scavenger receptor for aldehyde-modified proteins.

  12. Mild and efficient strategy for site-selective aldehyde modification of glycosaminoglycans: tailoring hydrogels with tunable release of growth factor.

    PubMed

    Wang, Shujiang; Oommen, Oommen P; Yan, Hongji; Varghese, Oommen P

    2013-07-01

    Aldehydes have been used as an important bioorthogonal chemical reporter for conjugation of large polymers and bioactive substances. However, generating aldehyde functionality on carbohydrate-based biopolymers without changing its native chemical structure has always persisted as a challenging task. The common methods employed to achieve this require harsh reaction conditions, which often compromise the structural integrity and biological function of these sensitive molecules. Here we report a mild and simple method to graft aldehydes groups on glycosaminoglycans (GAGs) in a site-selective manner without compromising the structural integrity of the biopolymer. This regio-selective modification was achieved by conjugating the amino-glycerol moiety on the carboxylate residue of the polymer, which allowed selective cleavage of pendent diol groups without interfering with the C2-C3 diol groups of the native glucopyranose residue. Kinetic evaluation of this reaction demonstrated significant differences in second-order reaction rate for periodate oxidation (by four-orders of magnitude) between the two types of vicinal diols. We employed this chemistry to develop aldehyde modifications of sulfated and nonsulfated GAGs such as hyaluronic acid (HA), heparin (HP), and chondroitin sulfate (CS). We further utilized these aldehyde grafted GAGs to tailor extracellular matrix mimetic injectable hydrogels and evaluated its rheological properties. The composition of the hydrogels was also found to modulate release of therapeutic protein such as FGF-2, demonstrating controlled release (60%) for over 14 days. In short, our result clearly demonstrates a versatile strategy to graft aldehyde groups on sensitive biopolymers under mild conditions that could be applied for various bioconjugation and biomedical applications such as drug delivery and regenerative medicine. PMID:23721079

  13. Mild and efficient strategy for site-selective aldehyde modification of glycosaminoglycans: tailoring hydrogels with tunable release of growth factor.

    PubMed

    Wang, Shujiang; Oommen, Oommen P; Yan, Hongji; Varghese, Oommen P

    2013-07-01

    Aldehydes have been used as an important bioorthogonal chemical reporter for conjugation of large polymers and bioactive substances. However, generating aldehyde functionality on carbohydrate-based biopolymers without changing its native chemical structure has always persisted as a challenging task. The common methods employed to achieve this require harsh reaction conditions, which often compromise the structural integrity and biological function of these sensitive molecules. Here we report a mild and simple method to graft aldehydes groups on glycosaminoglycans (GAGs) in a site-selective manner without compromising the structural integrity of the biopolymer. This regio-selective modification was achieved by conjugating the amino-glycerol moiety on the carboxylate residue of the polymer, which allowed selective cleavage of pendent diol groups without interfering with the C2-C3 diol groups of the native glucopyranose residue. Kinetic evaluation of this reaction demonstrated significant differences in second-order reaction rate for periodate oxidation (by four-orders of magnitude) between the two types of vicinal diols. We employed this chemistry to develop aldehyde modifications of sulfated and nonsulfated GAGs such as hyaluronic acid (HA), heparin (HP), and chondroitin sulfate (CS). We further utilized these aldehyde grafted GAGs to tailor extracellular matrix mimetic injectable hydrogels and evaluated its rheological properties. The composition of the hydrogels was also found to modulate release of therapeutic protein such as FGF-2, demonstrating controlled release (60%) for over 14 days. In short, our result clearly demonstrates a versatile strategy to graft aldehyde groups on sensitive biopolymers under mild conditions that could be applied for various bioconjugation and biomedical applications such as drug delivery and regenerative medicine.

  14. Betaine aldehyde dehydrogenase isozymes of spinach

    SciTech Connect

    Hanson, A.D.; Weretilnyk, E.A.; Weigel, P.

    1986-04-01

    Betaine is synthesized in spinach chloroplasts via the pathway Choline ..-->.. Betaine Aldehyde ..-->.. Betaine; the second step is catalyzed by betaine aldehyde dehydrogenase (BADH). The subcellular distribution of BADH was determined in leaf protoplast lysates; BADH isozymes were separated by 6-9% native PAGE. The chloroplast stromal fraction contains a single BADH isozyme (number1) that accounts for > 80% of the total protoplast activity; the extrachloroplastic fraction has a minor isozyme (number2) which migrates more slowly than number1. Both isozymes appear specific for betaine aldehyde, are more active with NAD than NADP, and show a ca. 3-fold activity increase in salinized leaves. The phenotype of a natural variant of isozyme number1 suggests that the enzyme is a dimer.

  15. A general method for synthesizing enzyme-polymer conjugates in reverse emulsions using Pluronic as a reactive surfactant.

    PubMed

    Wu, Xiaoling; Ge, Jun; Zhu, Jingying; Zhang, Yifei; Yong, You; Liu, Zheng

    2015-06-14

    Using aldehyde-functionalized Pluronic as the reactive surfactant, enzyme-Pluronic conjugates with sizes ranging from nanometers to micrometers were synthesized in reverse emulsions. Compared with the direct conjugation in aqueous solution, this method gave an increased conjugation efficiency and well-controlled size of the conjugates. The versatility of this method was validated using horseradish peroxidase (HRP), Candida rugosa lipase (CRL) and Candida antarctica lipase B (CALB). The resulting enzyme-Pluronic conjugates showed greatly enhanced apparent activity compared to free enzymes in organic media.

  16. Volatile aldehydes in libraries and archives

    NASA Astrophysics Data System (ADS)

    Fenech, Ann; Strlič, Matija; Kralj Cigić, Irena; Levart, Alenka; Gibson, Lorraine T.; de Bruin, Gerrit; Ntanos, Konstantinos; Kolar, Jana; Cassar, May

    2010-06-01

    Volatile aldehydes are produced during degradation of paper-based materials. This may result in their accumulation in archival and library repositories. However, no systematic study has been performed so far. In the frame of this study, passive sampling was carried out at ten locations in four libraries and archives. Despite the very variable sampling locations, no major differences were found, although air-filtered repositories were found to have lower concentrations while a non-ventilated newspaper repository exhibited the highest concentrations of volatile aldehydes (formaldehyde, acetaldehyde, furfural and hexanal). Five employees in one institution were also provided with personal passive samplers to investigate employees' exposure to volatile aldehydes. All values were lower than the presently valid exposure limits. The concentration of volatile aldehydes, acetic acid, and volatile organic compounds (VOCs) in general was also compared with that of outdoor-generated pollutants. It was evident that inside the repository and particularly inside archival boxes, the concentration of VOCs and acetic acid was much higher than the concentration of outdoor-generated pollutants, which are otherwise more routinely studied in connection with heritage materials. This indicates that further work on the pro-degradative effect of VOCs on heritage materials is necessary and that monitoring of VOCs in heritage institutions should become more widespread.

  17. Oxidation of Aromatic Aldehydes Using Oxone

    ERIC Educational Resources Information Center

    Gandhari, Rajani; Maddukuri, Padma P.; Thottumkara, Vinod K.

    2007-01-01

    The experiment demonstrating the feasibility of using water as a solvent for organic reactions which highlights the cost and environmental benefits of its use is presented. The experiment encourages students to think in terms of the reaction mechanism of the oxidation of aldehydes knowing that potassium persulfate is the active oxidant in Oxone…

  18. Stereoselective Synthesis of Conjugated Fluoro Enynes

    PubMed Central

    Kumar, Rakesh; Zajc, Barbara

    2013-01-01

    Metalation-electrophilic fluorination of TMS- and TIPS-protected 1,3-benzothiazol-2-yl (BT) propargyl sulfones gave corresponding BT fluoropropargyl sulfones, Julia-Kocienski reagents for the synthesis of fluoro enynes. Both reagents reacted with aldehydes under mild DBU, or LHMDS-mediated conditions, giving high yields of conjugated fluoro enynes with E- stereoselectivity. In comparison to DBU-mediated reactions, stereoselectivity was higher in low-temperature LHMDS-mediated reactions. Two ketones were shown to react as well, using LHMDS as base. In situ removal of the TMS group gave terminal conjugated 2-fluoro 1,3-enynes. Synthetic utility of the fluoro enynes was demonstrated by conversion to internal alkynes and to stereoisomeric fluoro dienes via Sonogashira and Heck couplings. PMID:23005035

  19. Aldehyde Reduction by Cytochrome P450

    PubMed Central

    Amunom, Immaculate; Srivastava, Sanjay; Prough, Russell A.

    2011-01-01

    This protocol describes the procedure for measuring the relative rates of metabolism of the α,β-unsaturated aldehydes, 9-anthracene aldehyde (9-AA) and 4-hydroxy-trans-2-nonenal (4-HNE); specifically the aldehyde reduction reactions of cytochrome P450s (CYPs). These assays can be performed using either liver microsomal or other tissue fractions, spherosome preparations of recombinant CYPs, or recombinant CYPs from other sources. The method used here to study the reduction of a model α,β-unsaturated aldehyde, 9-AA, by CYPs was adapted from the assay used to investigate 9-anthracene oxidation as reported by Marini et al. (Marini et al., 2003). For experiments measuring reduction of the endogenous aldehyde, 4-HNE, the substrate was incubated with CYP in the presence of oxygen and NADPH and the metabolites were separated by High Pressure Liquid Chromatograpy (HPLC), using an adaptation of the method of Srivastava et al. (Srivastava et al., 2010). For study of 9-AA and 4-HNE reduction, the first step involves incubation of the substrate with the CYP in appropriate media, followed by quantification of metabolites through either spectrofluorimetry or analysis by HPLC coupled with a radiometric assay, respectively. Metabolite identification can be achieved by HPLC GC-mass spectrometric analysis. Inhibitors of cytochrome P450 function can be utilized to show the role of the hemoprotein or other enzymes in these reduction reactions. The reduction reactions for CYP’s were not inhibited by either anaerobiosis or inclusion of CO in the gaseous phase of the reaction mixture. These character of these reactions are similar to those reported for some cytochrome P450-catalyzed azo reduction reactions. PMID:21553396

  20. 40 CFR 721.639 - Amine aldehyde condensate.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Amine aldehyde condensate. 721.639... Substances § 721.639 Amine aldehyde condensate. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an amine aldehyde condensate (PMN...

  1. 40 CFR 721.639 - Amine aldehyde condensate.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Amine aldehyde condensate. 721.639... Substances § 721.639 Amine aldehyde condensate. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an amine aldehyde condensate (PMN...

  2. 40 CFR 721.639 - Amine aldehyde condensate.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Amine aldehyde condensate. 721.639... Substances § 721.639 Amine aldehyde condensate. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an amine aldehyde condensate (PMN...

  3. 40 CFR 721.5762 - Aromatic aldehyde phenolic resin (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Aromatic aldehyde phenolic resin... Specific Chemical Substances § 721.5762 Aromatic aldehyde phenolic resin (generic). (a) Chemical substance... aromatic aldehyde phenolic resin (PMN P-01-573) is subject to reporting under this section for...

  4. 40 CFR 721.5762 - Aromatic aldehyde phenolic resin (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aromatic aldehyde phenolic resin... Specific Chemical Substances § 721.5762 Aromatic aldehyde phenolic resin (generic). (a) Chemical substance... aromatic aldehyde phenolic resin (PMN P-01-573) is subject to reporting under this section for...

  5. 40 CFR 721.5762 - Aromatic aldehyde phenolic resin (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Aromatic aldehyde phenolic resin... Specific Chemical Substances § 721.5762 Aromatic aldehyde phenolic resin (generic). (a) Chemical substance... aromatic aldehyde phenolic resin (PMN P-01-573) is subject to reporting under this section for...

  6. 40 CFR 721.5762 - Aromatic aldehyde phenolic resin (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Aromatic aldehyde phenolic resin... Specific Chemical Substances § 721.5762 Aromatic aldehyde phenolic resin (generic). (a) Chemical substance... aromatic aldehyde phenolic resin (PMN P-01-573) is subject to reporting under this section for...

  7. Enzyme-catalysed conjugations of glutathione with unsaturated compounds

    PubMed Central

    Boyland, E.; Chasseaud, L. F.

    1967-01-01

    1. Rat-liver supernatant catalyses the reaction of diethyl maleate with glutathione. 2. Evidence is presented that the enzyme involved is different from the known glutathione-conjugating enzymes, glutathione S-alkyltransferase, S-aryltransferase and S-epoxidetransferase. 3. Rat-liver supernatant catalyses the reaction of a number of other αβ-unsaturated compounds, including aldehydes, ketones, lactones, nitriles and nitro compounds, with glutathione: separate enzymes may be responsible for these reactions. PMID:6035529

  8. Bifunctional aldehyde/alcohol dehydrogenase (ADHE) in chlorophyte algal mitochondria.

    PubMed

    Atteia, Ariane; van Lis, Robert; Mendoza-Hernández, Guillermo; Henze, Katrin; Martin, William; Riveros-Rosas, Hector; González-Halphen, Diego

    2003-09-01

    Protein profiles of mitochondria isolated from the heterotrophic chlorophyte Polytomella sp. grown on ethanol at pH 6.0 and pH 3.7 were analyzed by Blue Native and denaturing polyacrylamide gel electrophoresis. Steady-state levels of oxidative phosphorylation complexes were influenced by external pH. Levels of an abundant, soluble, mitochondrial protein of 85 kDa and its corresponding mRNA increased at pH 6.0 relative to pH 3.7. N-terminal and internal sequencing of the 85 kDa mitochondrial protein together with the corresponding cDNA identified it as a bifunctional aldehyde/alcohol dehydrogenase (ADHE) with strong similarity to homologues from eubacteria and amitochondriate protists. A mitochondrial targeting sequence of 27 amino acids precedes the N-terminus of the mature mitochondrial protein. A gene encoding an ADHE homologue was also identified in the genome of Chlamydomonas reinhardtii, a photosynthetic relative of Polytomella. ADHE reveals a complex picture of sequence similarity among homologues. The lack of ADHE from archaebacteria indicates a eubacterial origin for the eukaryotic enzyme. Among eukaryotes, ADHE has hitherto been characteristic of anaerobes since it is essential to cytosolic energy metabolism of amitochondriate protists such as Giardia intestinalis and Entamoeba histolytica. Its abundance and expression pattern suggest an important role for ADHE in mitochondrial metabolism of Polytomella under the conditions studied. The current data are compatible with the view that Polytomella ADHE could be involved either in ethanol production or assimilation, or both, depending upon environmental conditions. Presence of ADHE in an oxygen-respiring algal mitochondrion and co-expression at ambient oxygen levels with respiratory chain components is unexpected with respect to the view that eukaryotes acquired ADHE genes specifically as an adaptation to an anaerobic lifestyle.

  9. Bifunctional aldehyde/alcohol dehydrogenase (ADHE) in chlorophyte algal mitochondria.

    PubMed

    Atteia, Ariane; van Lis, Robert; Mendoza-Hernández, Guillermo; Henze, Katrin; Martin, William; Riveros-Rosas, Hector; González-Halphen, Diego

    2003-09-01

    Protein profiles of mitochondria isolated from the heterotrophic chlorophyte Polytomella sp. grown on ethanol at pH 6.0 and pH 3.7 were analyzed by Blue Native and denaturing polyacrylamide gel electrophoresis. Steady-state levels of oxidative phosphorylation complexes were influenced by external pH. Levels of an abundant, soluble, mitochondrial protein of 85 kDa and its corresponding mRNA increased at pH 6.0 relative to pH 3.7. N-terminal and internal sequencing of the 85 kDa mitochondrial protein together with the corresponding cDNA identified it as a bifunctional aldehyde/alcohol dehydrogenase (ADHE) with strong similarity to homologues from eubacteria and amitochondriate protists. A mitochondrial targeting sequence of 27 amino acids precedes the N-terminus of the mature mitochondrial protein. A gene encoding an ADHE homologue was also identified in the genome of Chlamydomonas reinhardtii, a photosynthetic relative of Polytomella. ADHE reveals a complex picture of sequence similarity among homologues. The lack of ADHE from archaebacteria indicates a eubacterial origin for the eukaryotic enzyme. Among eukaryotes, ADHE has hitherto been characteristic of anaerobes since it is essential to cytosolic energy metabolism of amitochondriate protists such as Giardia intestinalis and Entamoeba histolytica. Its abundance and expression pattern suggest an important role for ADHE in mitochondrial metabolism of Polytomella under the conditions studied. The current data are compatible with the view that Polytomella ADHE could be involved either in ethanol production or assimilation, or both, depending upon environmental conditions. Presence of ADHE in an oxygen-respiring algal mitochondrion and co-expression at ambient oxygen levels with respiratory chain components is unexpected with respect to the view that eukaryotes acquired ADHE genes specifically as an adaptation to an anaerobic lifestyle. PMID:14756315

  10. Impact of reconstituted cytosol on protein stability

    PubMed Central

    Sarkar, Mohona; Smith, Austin E.; Pielak, Gary J.

    2013-01-01

    Protein stability is usually studied in simple buffered solutions, but most proteins function inside cells, where the heterogeneous and crowded environment presents a complex, nonideal system. Proteins are expected to behave differently under cellular crowding owing to two types of contacts: hard-core repulsions and weak, chemical interactions. The effect of hard-core repulsions is purely entropic, resulting in volume exclusion owing to the mere presence of the crowders. The weak interactions can be repulsive or attractive, thus enhancing or diminishing the excluded volume, respectively. We used a reductionist approach to assess the effects of intracellular crowding. Escherichia coli cytoplasm was dialyzed, lyophilized, and resuspended at two concentrations. NMR-detected amide proton exchange was then used to quantify the stability of the globular protein chymotrypsin inhibitor 2 (CI2) in these crowded solutions. The cytosol destabilizes CI2, and the destabilization increases with increasing cytosol concentration. This observation shows that the cytoplasm interacts favorably, but nonspecifically, with CI2, and these interactions overcome the stabilizing hard-core repulsions. The effects of the cytosol are even stronger than those of homogeneous protein crowders, reinforcing the biological significance of weak, nonspecific interactions. PMID:24218610

  11. Inhibition of human cytochrome P450 2E1 and 2A6 by aldehydes: structure and activity relationships.

    PubMed

    Kandagatla, Suneel K; Mack, Todd; Simpson, Sean; Sollenberger, Jill; Helton, Eric; Raner, Gregory M

    2014-08-01

    The purpose of this study was to probe active site structure and dynamics of human cytochrome P4502E1 and P4502A6 using a series of related short chain fatty aldehydes. Binding efficiency of the aldehydes was monitored via their ability to inhibit the binding and activation of the probe substrates p-nitrophenol (2E1) and coumarin (2A6). Oxidation of the aldehydes was observed in reactions with individually expressed 2E1, but not 2A6, suggesting alternate binding modes. For saturated aldehydes the optimum chain length for inhibition of 2E1 was 9 carbons (KI=7.8 ± 0.3 μM), whereas for 2A6 heptanal was most potent (KI=15.8 ± 1.1 μM). A double bond in the 2-position of the aldehyde significantly decreased the observed KI relative to the corresponding saturated compound in most cases. A clear difference in the effect of the double bond was observed between the two isoforms. With 2E1, the double bond appeared to remove steric constraints on aldehyde binding with KI values for the 5-12 carbon compounds ranging between 2.6 ± 0.1 μM and 12.8 ± 0.5 μM, whereas steric effects remained the dominant factor in the binding of the unsaturated aldehydes to 2A6 (observed KI values between 7.0 ± 0.5 μM and >1000 μM). The aldehyde function was essential for effective inhibition, as the corresponding carboxylic acids had very little effect on enzyme activity over the same range of concentrations, and branching at the 3-position of the aldehydes increased the corresponding KI value in all cases examined. The results suggest that a conjugated π-system may be a key structural determinant in the binding of these compounds to both enzymes, and may also be an important feature for the expansion of the active site volume in 2E1.

  12. Inhibition of human Cytochrome P450 2E1 and 2A6 by aldehydes: Structure and activity relationships

    PubMed Central

    Kandagatla, Suneel K.; Mack, Todd; Simpson, Sean; Sollenberger, Jill; Helton, Eric; Raner, Gregory M.

    2014-01-01

    The purpose of this study was to probe active site structure and dynamics of human cytochrome P4502E1 and P4502A6 using a series of related short chain fatty aldehydes. Binding efficiency of the aldehydes was monitored via their ability to inhibit the binding and activation of the probe substrates p-nitrophenol (2E1) and coumarin (2A6). Oxidation of the aldehydes was observed in reactions with individually expressed 2E1, but not 2A6, suggesting alternate binding modes. For saturated aldehydes the optimum chain length for inhibition of 2E1 was 9 carbons (KI=7.8 ±0.3 μM), whereas for 2A6 heptanal was most potent (KI=15.8 ±1.1 μM). A double bond in the 2-position of the aldehyde significantly decreased the observed KI relative to the corresponding saturated compound in most cases. A clear difference in the effect of the double bond was observed between the two isoforms. With 2E1, the double bond appeared to remove steric constraints on aldehyde binding with KI values for the 5–12 carbon compounds ranging between 2.6 ± 0.1 μM and 12.8± 0.5 μM, whereas steric effects remained the dominant factor in the binding of the unsaturated aldehydes to 2A6 (observed KI values between 7.0± 0.5 μM and >1000 μM). The aldehyde function was essential for effective inhibition, as the corresponding carboxylic acids had very little effect on enzyme activity over the same range of concentrations, and branching at the 3-position of the aldehydes increased the corresponding KI value in all cases examined. The results suggest that a conjugated π-system may be a key structural determinant in the binding of these compounds to both enzymes, and may also be an important feature for the expansion of the active site volume in 2E1. PMID:24924949

  13. Neurotoxicity of reactive aldehydes: the concept of "aldehyde load" as demonstrated by neuroprotection with hydroxylamines.

    PubMed

    Wood, Paul L; Khan, M Amin; Kulow, Sarah R; Mahmood, Siddique A; Moskal, Joseph R

    2006-06-20

    The concept of "oxidative stress" has become a mainstay in the field of neurodegeneration but has failed to differentiate critical events from epiphenomena and sequalae. Furthermore, the translation of current concepts of neurodegenerative mechanisms into effective therapeutics for neurodegenerative diseases has been meager and disappointing. A corollary of current concepts of "oxidative stress" is that of "aldehyde load". This relates to the production of reactive aldehydes that covalently modify proteins, nucleic acids, lipids and carbohydrates and activate apoptotic pathways. However, reactive aldehydes can also be generated by mechanisms other than "oxidative stress". We therefore hypothesized that agents that can chemically neutralize reactive aldehydes should demonstrate superior neuroprotective actions to those of free radical scavengers. To this end, we evaluated hydroxylamines as aldehyde-trapping agents in an in vitro model of neurodegeneration induced by the reactive aldehyde, 3-aminopropanal (3-AP), a product of polyamine oxidase metabolism of spermine and spermidine. In this model, the hydroxylamines N-benzylhydroxylamine, cyclohexylhydroxylamine and t-butylhydroxylamine were shown to protect, in a concentration-dependent manner, against 3-AP neurotoxicity. Additionally, a therapeutic window of 3 h was demonstrated for delayed administration of the hydroxylamines. In contrast, the free radical scavengers TEMPO and TEMPONE and the anti-oxidant ascorbic acid were ineffective in this model. Extending these tissue culture findings in vivo, we examined the actions of N-benzylhydroxylamine in the trimethyltin (TMT) rat model of hippocampal CA3 neurodegeneration. This model involves augmented polyamine metabolism resulting in the generation of reactive aldehydes that compromise mitochondrial integrity. In the rat TMT model, NBHA (50 mg/kg, sc, daily) provided 100% protection against neurodegeneration, as reflected by measurements of KCl-evoked glutamate

  14. SAXS fingerprints of aldehyde dehydrogenase oligomers

    PubMed Central

    Tanner, John J.

    2015-01-01

    Enzymes of the aldehyde dehydrogenase (ALDH) superfamily catalyze the nicotinamide adenine dinucleotide-dependent oxidation of aldehydes to carboxylic acids. ALDHs are important in detoxification of aldehydes, amino acid metabolism, embryogenesis and development, neurotransmission, oxidative stress, and cancer. Mutations in genes encoding ALDHs cause metabolic disorders, including alcohol flush reaction (ALDH2), Sjögren–Larsson syndrome (ALDH3A2), hyperprolinemia type II (ALDH4A1), γ-hydroxybutyric aciduria (ALDH5A1), methylmalonic aciduria (ALDH6A1), pyridoxine dependent epilepsy (ALDH7A1), and hyperammonemia (ALDH18A1). We previously reported crystal structures and small-angle X-ray scattering (SAXS) analyses of ALDHs exhibiting dimeric, tetrameric, and hexameric oligomeric states (Luo et al., Biochemistry 54 (2015) 5513–5522; Luo et al., J. Mol. Biol. 425 (2013) 3106–3120). Herein I provide the SAXS curves, radii of gyration, and distance distribution functions for the three types of ALDH oligomer. The SAXS curves and associated analysis provide diagnostic fingerprints that allow rapid identification of the type of ALDH oligomer that is present in solution. The data sets provided here serve as a benchmark for characterizing oligomerization of ALDHs. PMID:26693506

  15. SAXS fingerprints of aldehyde dehydrogenase oligomers.

    PubMed

    Tanner, John J

    2015-12-01

    Enzymes of the aldehyde dehydrogenase (ALDH) superfamily catalyze the nicotinamide adenine dinucleotide-dependent oxidation of aldehydes to carboxylic acids. ALDHs are important in detoxification of aldehydes, amino acid metabolism, embryogenesis and development, neurotransmission, oxidative stress, and cancer. Mutations in genes encoding ALDHs cause metabolic disorders, including alcohol flush reaction (ALDH2), Sjögren-Larsson syndrome (ALDH3A2), hyperprolinemia type II (ALDH4A1), γ-hydroxybutyric aciduria (ALDH5A1), methylmalonic aciduria (ALDH6A1), pyridoxine dependent epilepsy (ALDH7A1), and hyperammonemia (ALDH18A1). We previously reported crystal structures and small-angle X-ray scattering (SAXS) analyses of ALDHs exhibiting dimeric, tetrameric, and hexameric oligomeric states (Luo et al., Biochemistry 54 (2015) 5513-5522; Luo et al., J. Mol. Biol. 425 (2013) 3106-3120). Herein I provide the SAXS curves, radii of gyration, and distance distribution functions for the three types of ALDH oligomer. The SAXS curves and associated analysis provide diagnostic fingerprints that allow rapid identification of the type of ALDH oligomer that is present in solution. The data sets provided here serve as a benchmark for characterizing oligomerization of ALDHs. PMID:26693506

  16. IN VITRO ORGANIC NITRATE BIOACTIVATION TO NITRIC OXIDE BY RECOMBINANT ALDEHYDE DEHYDROGENASE 3A1

    PubMed Central

    Lin, Shunxin; Page, Nathaniel A.; Fung, Sun Mi; Fung, Ho-Leung

    2013-01-01

    Organic nitrates (ORNs) are commonly used anti-ischemic and anti-anginal agents, which serve as an exogenous source of the potent vasodilator nitric oxide (NO). Recently, both mitochondrial aldehyde dehydrogenase-2 (ALDH2) and cytosolic aldehyde dehydrogenase-1a1 (ALDH1A1) have been shown to exhibit the ability to selectively bioactivate various ORNs in vitro. The objective of the present research was to examine the potential role of ALDH3A1, another major cytosolic isoform of ALDH, in the in vitro bioactivation of various ORNs, and to estimate the enzyme kinetic parameters toward ORNs through mechanistic modeling. The extent of bioactivation was assayed by exposing recombinant ALDH3A1 to various concentrations of ORNs, and measuring the concentration-time profiles of released NO via a NO-specific electrode. Metabolite formation kinetics was monitored for nitroglycerin (NTG) using LC/MS/MS. Our results showed that ALDH3A1 mRNA and protein were highly expressed in C57BL/6 mouse aortic, cardiac, and hepatic tissues, and it was able to release NO from several ORNs, including NTG, isosorbide dinitrate (ISDN), isosorbide-2-mononitrate (IS-2-MN), and nicorandil with similar Vmax (0.175 – 0.503 nmol/min/mg of ALDH3A1), and Km values of 4.01, 46.5, 818 and 5.75 × 103 μM respectively. However, activation of isosorbide-5-mononitrate (IS-5-MN) by ALDH3A1 was undetectable in vitro. ALDH3A1 was also shown to denitrate NTG, producing primarily glyceryl 1, 2-dinitrate (1, 2-GDN) in preference to glyceryl 1, 3-dinitrate (1, 3-GDN). Therefore, ALDH3A1 may contribute to the bioactivation of ORNs in vivo. PMID:24126018

  17. Myeloperoxidase-dependent Lipid Peroxidation Promotes the Oxidative Modification of Cytosolic Proteins in Phagocytic Neutrophils*

    PubMed Central

    Wilkie-Grantham, Rachel P.; Magon, Nicholas J.; Harwood, D. Tim; Kettle, Anthony J.; Vissers, Margreet C.; Winterbourn, Christine C.; Hampton, Mark B.

    2015-01-01

    Phagocytic neutrophils generate reactive oxygen species to kill microbes. Oxidant generation occurs within an intracellular phagosome, but diffusible species can react with the neutrophil and surrounding tissue. To investigate the extent of oxidative modification, we assessed the carbonylation of cytosolic proteins in phagocytic neutrophils. A 4-fold increase in protein carbonylation was measured within 15 min of initiating phagocytosis. Carbonylation was dependent on NADPH oxidase and myeloperoxidase activity and was inhibited by butylated hydroxytoluene and Trolox, indicating a role for myeloperoxidase-dependent lipid peroxidation. Proteomic analysis of target proteins revealed significant carbonylation of the S100A9 subunit of calprotectin, a truncated form of Hsp70, actin, and hemoglobin from contaminating erythrocytes. The addition of the reactive aldehyde 4-hydroxynonenal (HNE) caused carbonylation, and HNE-glutathione adducts were detected in the cytosol of phagocytic neutrophils. The post-translational modification of neutrophil proteins will influence the functioning and fate of these immune cells in the period following phagocytic activation, and provides a marker of neutrophil activation during infection and inflammation. PMID:25697357

  18. One-Pot Amide Bond Formation from Aldehydes and Amines via a Photoorganocatalytic Activation of Aldehydes.

    PubMed

    Papadopoulos, Giorgos N; Kokotos, Christoforos G

    2016-08-19

    A mild, one-pot, and environmentally friendly synthesis of amides from aldehydes and amines is described. Initially, a photoorganocatalytic reaction of aldehydes with di-isopropyl azodicarboxylate leads to an intermediate carbonyl imide, which can react with a variety of amines to afford the desired amides. The initial visible light-mediated activation of a variety of monosubstituted or disubstituted aldehydes is usually fast, occurring in a few hours. Following the photocatalytic reaction, addition of the primary amine at room temperature or the secondary amine at elevated temperatures leads to the corresponding amide from moderate to excellent yields without epimerization. This methodology was applied in the synthesis of Moclobemide, a drug against depression and social anxiety. PMID:27227271

  19. An integrated QSAR-PBK/D modelling approach for predicting detoxification and DNA adduct formation of 18 acyclic food-borne α,β-unsaturated aldehydes

    SciTech Connect

    Kiwamoto, R. Spenkelink, A.; Rietjens, I.M.C.M.; Punt, A.

    2015-01-01

    Acyclic α,β-unsaturated aldehydes present in food raise a concern because the α,β-unsaturated aldehyde moiety is considered a structural alert for genotoxicity. However, controversy remains on whether in vivo at realistic dietary exposure DNA adduct formation is significant. The aim of the present study was to develop physiologically based kinetic/dynamic (PBK/D) models to examine dose-dependent detoxification and DNA adduct formation of a group of 18 food-borne acyclic α,β-unsaturated aldehydes without 2- or 3-alkylation, and with no more than one conjugated double bond. Parameters for the PBK/D models were obtained using quantitative structure–activity relationships (QSARs) defined with a training set of six selected aldehydes. Using the QSARs, PBK/D models for the other 12 aldehydes were defined. Results revealed that DNA adduct formation in the liver increases with decreasing bulkiness of the molecule especially due to less efficient detoxification. 2-Propenal (acrolein) was identified to induce the highest DNA adduct levels. At realistic dietary intake, the predicted DNA adduct levels for all aldehydes were two orders of magnitude lower than endogenous background levels observed in disease free human liver, suggesting that for all 18 aldehydes DNA adduct formation is negligible at the relevant levels of dietary intake. The present study provides a proof of principle for the use of QSAR-based PBK/D modelling to facilitate group evaluations and read-across in risk assessment. - Highlights: • Physiologically based in silico models were made for 18 α,β-unsaturated aldehydes. • Kinetic parameters were determined by in vitro incubations and a QSAR approach. • DNA adduct formation was negligible at levels relevant for dietary intake. • The use of QSAR-based PBK/D modelling facilitates group evaluations and read-across.

  20. Betaine Accumulation and Betaine-Aldehyde Dehydrogenase in Spinach Leaves 1

    PubMed Central

    Pan, Shu-Mei; Moreau, Robert A.; Yu, Charles; Huang, Anthony H. C.

    1981-01-01

    Spinach leaf discs accumulated betaine when exposed to a mannitol solution of −20 bars. The accumulation was 12 micromoles per gram original fresh weight in a 24-hour period. Betaine-aldehyde dehydrogenase (EC 1.2.1.8) was assayed in various subcellular fractions prepared from spinach leaves, and it was found only in the soluble fraction. This cytosolic enzyme was purified 175-fold, and its properties were studied. The enzyme was relatively specific for betaine aldehyde as the substrate with an apparent Km value of 2.08 × 10−4 molar. It also exerted activity on other aldehyde analogs tested, but with lower Vmax and higher Km values. The enzyme was relatively specific for nicotinamide adenine dinucleotide as the coenzyme, having an apparent Km value of 9.46 × 10−6 molar; lower activities were observed when nicotinamide adenine dinucleotide phosphate or 3-acetyl pyridine adenine dinucleotide were tested as electron acceptors. The activity was enhanced by dithiothreitol and inhibited by p-chloromercuribenzoate, and the inhibition by p-chloromercuribenzoate was partially reversed by the subsequent addition of dithiothreitol. The activity was inhibited by high concentrations of NaCl and, to a lesser extent, proline. The equilibrium of the enzymic reaction was strongly in favor of betaine formation. The in vitro activity of the enzyme under optimal assay conditions was high enough to account for the amount of betaine accumulated under water stress conditions. The enzyme activity was the same in unstressed leaves and in leaves that had been water stressed for 24 hours. PMID:16661818

  1. An aldehyde group-based P-acid probe for selective fluorescence turn-on sensing of cysteine and homocysteine.

    PubMed

    Yang, Chunlei; Wang, Xiu; Shen, Lei; Deng, Wenping; Liu, Haiyun; Ge, Shenguang; Yan, Mei; Song, Xianrang

    2016-06-15

    A highly sensitive and selective turn on fluorescent probe P-acid-aldehyde (P-CHO) is developed for the determination of cysteine (Cys) and homocysteine (Hcy). The probe is designed and synthesized by incorporating the specific functional group aldehyde group for thiols into a stable π-conjugated material 4,4'-(2,5-dimethoxy-1,4-phenylene) bis(ethyne-2,1-diyl) dibenzoic acid (P-acid). The probe fluorescence is quenched through donor photoinduced electron transfer (d-PET) between the fluorophore (P-acid) and the recognition group (aldehyde group). In the presence of thiols, Cys and Hcy can selectively react with aldehyde group of the probe because the inhibition of d-PET between fluorophore and recognition group. Therefore, a turn-on fluorescent sensor was established for the fluorescence recovery. Under the optimized conditions, the fluorescence response of probe is directly proportional to the concentration of Cys in the range of 4-95 NM L(-1), with a detection limit 3.0 nM. In addition, the sensing system exhibits good selectively toward Cys and Hcy in the presence of other amino acids. It has been successfully applied for bioimaging of Cys and Hcy in living cells with low cell toxicity.

  2. A pathogenesis related-10 protein CaARP functions as aldo/keto reductase to scavenge cytotoxic aldehydes.

    PubMed

    Jain, Deepti; Khandal, Hitaishi; Khurana, Jitendra Paul; Chattopadhyay, Debasis

    2016-01-01

    Pathogenesis related-10 (PR-10) proteins are present as multigene family in most of the higher plants. The role of PR-10 proteins in plant is poorly understood. A sequence analysis revealed that a large number of PR-10 proteins possess conserved motifs found in aldo/keto reductases (AKRs) of yeast and fungi. We took three PR-10 proteins, CaARP from chickpea, ABR17 from pea and the major pollen allergen Bet v1 from silver birch as examples and showed that these purified recombinant proteins possessed AKR activity using various cytotoxic aldehydes including methylglyoxal and malondialdehyde as substrates and the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) as co-factor. Essential amino acids for this catalytic activity were identified by substitution with other amino acids. CaARP was able to discriminate between the reduced and oxidized forms of NADP independently of its catalytic activity and underwent structural change upon binding with NADPH. CaARP protein was preferentially localized in cytosol. When expressed in bacteria, yeast or plant, catalytically active variants of CaARP conferred tolerance to salinity, oxidative stress or cytotoxic aldehydes. CaARP-expressing plants showed lower lipid peroxidation product content in presence or absence of stress suggesting that the protein functions as a scavenger of cytotoxic aldehydes produced by metabolism and lipid peroxidation. Our result proposes a new biochemical property of a PR-10 protein.

  3. A pathogenesis related-10 protein CaARP functions as aldo/keto reductase to scavenge cytotoxic aldehydes.

    PubMed

    Jain, Deepti; Khandal, Hitaishi; Khurana, Jitendra Paul; Chattopadhyay, Debasis

    2016-01-01

    Pathogenesis related-10 (PR-10) proteins are present as multigene family in most of the higher plants. The role of PR-10 proteins in plant is poorly understood. A sequence analysis revealed that a large number of PR-10 proteins possess conserved motifs found in aldo/keto reductases (AKRs) of yeast and fungi. We took three PR-10 proteins, CaARP from chickpea, ABR17 from pea and the major pollen allergen Bet v1 from silver birch as examples and showed that these purified recombinant proteins possessed AKR activity using various cytotoxic aldehydes including methylglyoxal and malondialdehyde as substrates and the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) as co-factor. Essential amino acids for this catalytic activity were identified by substitution with other amino acids. CaARP was able to discriminate between the reduced and oxidized forms of NADP independently of its catalytic activity and underwent structural change upon binding with NADPH. CaARP protein was preferentially localized in cytosol. When expressed in bacteria, yeast or plant, catalytically active variants of CaARP conferred tolerance to salinity, oxidative stress or cytotoxic aldehydes. CaARP-expressing plants showed lower lipid peroxidation product content in presence or absence of stress suggesting that the protein functions as a scavenger of cytotoxic aldehydes produced by metabolism and lipid peroxidation. Our result proposes a new biochemical property of a PR-10 protein. PMID:26577640

  4. Cytosolic Selection Systems To Study Protein Stability

    PubMed Central

    Malik, Ajamaluddin; Mueller-Schickert, Antje

    2014-01-01

    Here we describe biosensors that provide readouts for protein stability in the cytosolic compartment of prokaryotes. These biosensors consist of tripartite sandwich fusions that link the in vitro stability or aggregation susceptibility of guest proteins to the in vivo resistance of host cells to the antibiotics kanamycin, spectinomycin, and nourseothricin. These selectable markers confer antibiotic resistance in a wide range of hosts and are easily quantifiable. We show that mutations within guest proteins that affect their stability alter the antibiotic resistances of the cells expressing the biosensors in a manner that is related to the in vitro stabilities of the mutant guest proteins. In addition, we find that polyglutamine tracts of increasing length are associated with an increased tendency to form amyloids in vivo and, in our sandwich fusion system, with decreased resistance to aminoglycoside antibiotics. We demonstrate that our approach allows the in vivo analysis of protein stability in the cytosolic compartment without the need for prior structural and functional knowledge. PMID:25266385

  5. A coniferyl aldehyde dehydrogenase gene from Pseudomonas sp. strain HR199 enhances the conversion of coniferyl aldehyde by Saccharomyces cerevisiae.

    PubMed

    Adeboye, Peter Temitope; Olsson, Lisbeth; Bettiga, Maurizio

    2016-07-01

    The conversion of coniferyl aldehyde to cinnamic acids by Saccharomyces cerevisiae under aerobic growth conditions was previously observed. Bacteria such as Pseudomonas have been shown to harbor specialized enzymes for converting coniferyl aldehyde but no comparable enzymes have been identified in S. cerevisiae. CALDH from Pseudomonas was expressed in S. cerevisiae. An acetaldehyde dehydrogenase (Ald5) was also hypothesized to be actively involved in the conversion of coniferyl aldehyde under aerobic growth conditions in S. cerevisiae. In a second S. cerevisiae strain, the acetaldehyde dehydrogenase (ALD5) was deleted. A prototrophic control strain was also engineered. The engineered S. cerevisiae strains were cultivated in the presence of 1.1mM coniferyl aldehyde under aerobic condition in bioreactors. The results confirmed that expression of CALDH increased endogenous conversion of coniferyl aldehyde in S. cerevisiae and ALD5 is actively involved with the conversion of coniferyl aldehyde in S. cerevisiae. PMID:27070284

  6. Cytosolic delivery of materials with endosome-disrupting colloids

    DOEpatents

    Helms, Brett A.; Bayles, Andrea R.

    2016-03-15

    A facile procedure to deliver nanocrystals to the cytosol of live cells that is both rapid and general. The technique employs a unique cationic core-shell polymer colloid that directs nanocrystals to the cytosol of living cells within a few hours of incubation. The present methods and compositions enable a host of advanced applications arising from efficient cytosolic delivery of nanocrystal imaging probes: from single particle tracking experiments to monitoring protein-protein interactions in live cells for extended periods.

  7. Targeting Aldehyde Dehydrogenase 2: New Therapeutic Opportunities

    PubMed Central

    Chen, Che-Hong; Ferreira, Julio Cesar Batista; Gross, Eric R.; Mochly-Rosen, Daria

    2014-01-01

    A family of detoxifying enzymes called aldehyde dehydrogenases (ALDHs) has been a subject of recent interest, as its role in detoxifying aldehydes that accumulate through metabolism and to which we are exposed from the environment has been elucidated. Although the human genome has 19 ALDH genes, one ALDH emerges as a particularly important enzyme in a variety of human pathologies. This ALDH, ALDH2, is located in the mitochondrial matrix with much known about its role in ethanol metabolism. Less known is a new body of research to be discussed in this review, suggesting that ALDH2 dysfunction may contribute to a variety of human diseases including cardiovascular diseases, diabetes, neurodegenerative diseases, stroke, and cancer. Recent studies suggest that ALDH2 dysfunction is also associated with Fanconi anemia, pain, osteoporosis, and the process of aging. Furthermore, an ALDH2 inactivating mutation (termed ALDH2*2) is the most common single point mutation in humans, and epidemiological studies suggest a correlation between this inactivating mutation and increased propensity for common human pathologies. These data together with studies in animal models and the use of new pharmacological tools that activate ALDH2 depict a new picture related to ALDH2 as a critical health-promoting enzyme. PMID:24382882

  8. Relationships within the aldehyde dehydrogenase extended family.

    PubMed

    Perozich, J; Nicholas, H; Wang, B C; Lindahl, R; Hempel, J

    1999-01-01

    One hundred-forty-five full-length aldehyde dehydrogenase-related sequences were aligned to determine relationships within the aldehyde dehydrogenase (ALDH) extended family. The alignment reveals only four invariant residues: two glycines, a phenylalanine involved in NAD binding, and a glutamic acid that coordinates the nicotinamide ribose in certain E-NAD binary complex crystal structures, but which may also serve as a general base for the catalytic reaction. The cysteine that provides the catalytic thiol and its closest neighbor in space, an asparagine residue, are conserved in all ALDHs with demonstrated dehydrogenase activity. Sixteen residues are conserved in at least 95% of the sequences; 12 of these cluster into seven sequence motifs conserved in almost all ALDHs. These motifs cluster around the active site of the enzyme. Phylogenetic analysis of these ALDHs indicates at least 13 ALDH families, most of which have previously been identified but not grouped separately by alignment. ALDHs cluster into two main trunks of the phylogenetic tree. The largest, the "Class 3" trunk, contains mostly substrate-specific ALDH families, as well as the class 3 ALDH family itself. The other trunk, the "Class 1/2" trunk, contains mostly variable substrate ALDH families, including the class 1 and 2 ALDH families. Divergence of the substrate-specific ALDHs occurred earlier than the division between ALDHs with broad substrate specificities. A site on the World Wide Web has also been devoted to this alignment project.

  9. Catalytic asymmetric Michael addition of α,β-unsaturated aldehydes to Ni(II) complexes of the Schiff base of glycine.

    PubMed

    Luo, Xiaoyan; Jin, Zhichao; Li, Pengfei; Gao, Jiabin; Yue, Weimin; Liang, Xinmiao; Ye, Jinxing

    2011-02-01

    The conjugate addition of Ni(II) complexes of glycine Schiff base to α,β-unsaturated aldehydes catalyzed by (S)-2-(diphenyl(trimethylsilyloxy)methyl)pyrrolidine afforded adducts in excellent yields with up to 49:1 dr and 95% ee. This method enables the construction of two adjacent chiral centers in one step, and offers an alternative route to chiral α-amino acid derivatives. PMID:21103550

  10. Fine tuning of cytosolic Ca 2+ oscillations

    PubMed Central

    Dupont, Geneviève; Combettes, Laurent

    2016-01-01

    Ca 2+ oscillations, a widespread mode of cell signaling, were reported in non-excitable cells for the first time more than 25 years ago. Their fundamental mechanism, based on the periodic Ca 2+ exchange between the endoplasmic reticulum and the cytoplasm, has been well characterized. However, how the kinetics of cytosolic Ca 2+ changes are related to the extent of a physiological response remains poorly understood. Here, we review data suggesting that the downstream targets of Ca 2+ are controlled not only by the frequency of Ca 2+ oscillations but also by the detailed characteristics of the oscillations, such as their duration, shape, or baseline level. Involvement of non-endoplasmic reticulum Ca 2+ stores, mainly mitochondria and the extracellular medium, participates in this fine tuning of Ca 2+ oscillations. The main characteristics of the Ca 2+ exchange fluxes with these compartments are also reviewed.

  11. Fine tuning of cytosolic Ca (2+) oscillations.

    PubMed

    Dupont, Geneviève; Combettes, Laurent

    2016-01-01

    Ca (2+) oscillations, a widespread mode of cell signaling, were reported in non-excitable cells for the first time more than 25 years ago. Their fundamental mechanism, based on the periodic Ca (2+) exchange between the endoplasmic reticulum and the cytoplasm, has been well characterized. However, how the kinetics of cytosolic Ca (2+) changes are related to the extent of a physiological response remains poorly understood. Here, we review data suggesting that the downstream targets of Ca (2+) are controlled not only by the frequency of Ca (2+) oscillations but also by the detailed characteristics of the oscillations, such as their duration, shape, or baseline level. Involvement of non-endoplasmic reticulum Ca (2+) stores, mainly mitochondria and the extracellular medium, participates in this fine tuning of Ca (2+) oscillations. The main characteristics of the Ca (2+) exchange fluxes with these compartments are also reviewed. PMID:27630768

  12. Fine tuning of cytosolic Ca 2+ oscillations

    PubMed Central

    Dupont, Geneviève; Combettes, Laurent

    2016-01-01

    Ca 2+ oscillations, a widespread mode of cell signaling, were reported in non-excitable cells for the first time more than 25 years ago. Their fundamental mechanism, based on the periodic Ca 2+ exchange between the endoplasmic reticulum and the cytoplasm, has been well characterized. However, how the kinetics of cytosolic Ca 2+ changes are related to the extent of a physiological response remains poorly understood. Here, we review data suggesting that the downstream targets of Ca 2+ are controlled not only by the frequency of Ca 2+ oscillations but also by the detailed characteristics of the oscillations, such as their duration, shape, or baseline level. Involvement of non-endoplasmic reticulum Ca 2+ stores, mainly mitochondria and the extracellular medium, participates in this fine tuning of Ca 2+ oscillations. The main characteristics of the Ca 2+ exchange fluxes with these compartments are also reviewed. PMID:27630768

  13. Revisiting conjugate schedules.

    PubMed

    MacAleese, Kenneth R; Ghezzi, Patrick M; Rapp, John T

    2015-07-01

    The effects of conjugate reinforcement on the responding of 13 college students were examined in three experiments. Conjugate reinforcement was provided via key presses that changed the clarity of pictures displayed on a computer monitor in a manner proportional to the rate of responding. Experiment 1, which included seven parameters of clarity change per response, revealed that responding decreased as the percentage clarity per response increased for all five participants. These results indicate that each participant's responding was sensitive to intensity change, which is a parameter of conjugate reinforcement schedules. Experiment 2 showed that responding increased during conjugate reinforcement phases and decreased during extinction phases for all four participants. Experiment 3 also showed that responding increased during conjugate reinforcement and further showed that responding decreased during a conjugate negative punishment condition for another four participants. Directions for future research with conjugate schedules are briefly discussed. PMID:26150349

  14. Revisiting conjugate schedules.

    PubMed

    MacAleese, Kenneth R; Ghezzi, Patrick M; Rapp, John T

    2015-07-01

    The effects of conjugate reinforcement on the responding of 13 college students were examined in three experiments. Conjugate reinforcement was provided via key presses that changed the clarity of pictures displayed on a computer monitor in a manner proportional to the rate of responding. Experiment 1, which included seven parameters of clarity change per response, revealed that responding decreased as the percentage clarity per response increased for all five participants. These results indicate that each participant's responding was sensitive to intensity change, which is a parameter of conjugate reinforcement schedules. Experiment 2 showed that responding increased during conjugate reinforcement phases and decreased during extinction phases for all four participants. Experiment 3 also showed that responding increased during conjugate reinforcement and further showed that responding decreased during a conjugate negative punishment condition for another four participants. Directions for future research with conjugate schedules are briefly discussed.

  15. Appearance of aldehydes in the surface layer of lake waters.

    PubMed

    Dąbrowska, Agata; Nawrocki, Jacek; Szeląg-Wasielewska, Elżbieta

    2014-07-01

    The paper presents results concerning the changes in the content of aldehydes in samples of lake water collected near the lake surface. The study of lake waters was undertaken to explain which physicochemical parameters of the environment have the greatest influence on the level of aldehydes, which of the aldehydes are most often met in surface water and in what concentrations. We observed that formaldehyde, acetaldehyde, propanal, glyoxal, methylglyoxal and acetone were commonly present in surface water samples, while semi-volatile and poorly soluble aldehydes such as nonanal and decanal were observed seasonally. The contents of total aldehydes varied in a wide range, from 55 to 670 μg/l, and the concentration of total organic carbon varied significantly from 3 to 18 mg /l, but there was no evident correlation between them in all of samples. The total content of aldehydes did not depend on the meteorological parameters such as air temperature, UV radiation and ozone concentration; however, it was noted that the level of carbonyl concentration is related to the period of intense precipitation: in the period of very low precipitations, the highest contents of total aldehydes were determined in all of the water samples, and in the periods of intense precipitations, the content of total aldehydes was drastically smaller.

  16. 40 CFR 721.639 - Amine aldehyde condensate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.639 Amine aldehyde condensate. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an amine aldehyde condensate (PMN...

  17. 40 CFR 721.639 - Amine aldehyde condensate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.639 Amine aldehyde condensate. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an amine aldehyde condensate (PMN...

  18. DEVELOPMENTAL EXPRESSION OF ALDEHYDE DEHYDROGENASE IN RAT: A COMPARISON OF LIVER AND LUNG DEVELOPMENT

    EPA Science Inventory

    Metabolism is one of the major determinants for age-related susceptibility changes to chemicals. Aldehydes are highly reactive molecules present in the environment and can be produced during biotransformation of xenobiotics. Aldehyde dehydrogenases (ALDH) are important in aldehyd...

  19. Syntheses of [omega]-alkynyl aldehydes and ketones via oxidation of [omega]-alkynyl alcohols with pyridinium dichromate

    SciTech Connect

    Bierer, D.E.; Kabalka, G.W. )

    1988-01-01

    Pyridinium dichromate (PDC) is an effective reagent for the oxidation of alcohols and a number of modifications of the original procedure have been reported. Interestingly, PDC has never been used to oxidize non-conjugated acetylenic alcohols. As a part of a project involving the chemical preparation of a number of unsaturated amino acids, the authors investigated the synthesis of a series of [omega]-alkynyl aldehydes. The authors now report that the PDC oxidation of [omega]-alkynyl alcohols is an effective route to the corresponding [omega]-alkynyl carbonyl compounds.

  20. The Aldehyde Dehydrogenase Gene Superfamily Resource Center

    PubMed Central

    2009-01-01

    The website http://www.aldh.org is a publicly available database for nomenclature and functional and molecular sequence information for members of the aldehyde dehydrogenase (ALDH) gene superfamily for animals, plants, fungi and bacteria. The site has organised gene-specific records. It provides synopses of ALDH gene records, marries trivial terms to correct nomenclature and links global accession identifiers with source data. Server-side alignment software characterises the integrity of each sequence relative to the latest genomic assembly and provides identifier-specific detail reports, including a graphical presentation of the transcript's exon - intron structure, its size, coding sequence, genomic strand and locus. Also included are a summary of substrates, inhibitors and enzyme kinetics. The site provides reference lists and is designed to facilitate data mining by interested investigators. PMID:20038501

  1. New tyrosinase inhibitors, (+)-catechin-aldehyde polycondensates.

    PubMed

    Kim, Young-Jin; Chung, Joo Eun; Kurisawa, Motoichi; Uyama, Hiroshi; Kobayashi, Shiro

    2004-01-01

    In this study, new tyrosinase inhibitors, (+)-catechin-aldehyde polycondensates, have been developed. Tyrosinase is a copper-containing enzyme that catalyzes the hydroxylation of a monophenol (monophenolase activity) and the oxidation of an o-diphenol (diphenolase activity). In the measurement of tyrosinase inhibition activity, (+)-catechin acted as substrate and cofactor of tyrosinase. On the other hand, the polycondensates inhibited the tyrosine hydroxylation and L-DOPA oxidation by chelation to the active site of tyrosinase. The UV-visible spectrum of a mixture of tyrosinase and the polycondensate exhibited a characteristic shoulder peak ascribed to the chelation of the polycondensate to the active site of tyrosinase. Furthermore, circular dichroism measurement showed a small red shift of the band due to the interaction between tyrosinase and the polycondensate. These data support that the polycondensate acts as an inhibitor of tyrosinase. PMID:15003008

  2. Radical addition-initiated domino reactions of conjugated oxime ethers.

    PubMed

    Ueda, Masafumi

    2014-01-01

    The application of conjugated oxime ethers to the synthesis of complex chemical scaffolds using domino radical reactions has been described in detail. The triethylborane-mediated hydroxysulfenylation reaction allows for the regioselective construction of a carbon-sulfur bond and a carbon-oxygen bond in a single operation for the formation of β-hydroxy sulfides. This reaction proceeds via a radical pathway involving regioselective thiyl addition and the subsequent trapping of the resulting α-imino radical with O₂, where the imino group enhances the stability of the intermediate radical. Hydroxyalkylation reactions that occur via a carbon radical addition reaction followed by the hydroxylation of the resulting N-borylenamine with O₂ have also been developed. We investigated sequential radical addition aldol-type reactions in detail to explore the novel domino reactions that occur via the generation of N-borylenamine. The radical reaction of a conjugated oxime ether with triethylborane in the presence of an aldehyde affords γ-butyrolactone via sequential processes including ethyl radical addition, the generation of N-borylenamine, an aldol-type reaction with an aldehyde, and a lactonization reaction. A novel domino reaction has also been developed involving the [3,3]-sigmatropic rearrangement of N-boryl-N-phenoxyenamine. The triethylborane-mediated domino reactions of O-phenyl-conjugated oxime ethers afforded the corresponding benzofuro[2,3-b]pyrrol-2-ones via a radical addition/[3,3]-sigmatropic rearrangement/cyclization/lactamization cascade.

  3. Reversible, partial inactivation of plant betaine aldehyde dehydrogenase by betaine aldehyde: mechanism and possible physiological implications.

    PubMed

    Zárate-Romero, Andrés; Murillo-Melo, Darío S; Mújica-Jiménez, Carlos; Montiel, Carmina; Muñoz-Clares, Rosario A

    2016-04-01

    In plants, the last step in the biosynthesis of the osmoprotectant glycine betaine (GB) is the NAD(+)-dependent oxidation of betaine aldehyde (BAL) catalysed by some aldehyde dehydrogenase (ALDH) 10 enzymes that exhibit betaine aldehyde dehydrogenase (BADH) activity. Given the irreversibility of the reaction, the short-term regulation of these enzymes is of great physiological relevance to avoid adverse decreases in the NAD(+):NADH ratio. In the present study, we report that the Spinacia oleracea BADH (SoBADH) is reversibly and partially inactivated by BAL in the absence of NAD(+)in a time- and concentration-dependent mode. Crystallographic evidence indicates that the non-essential Cys(450)(SoBADH numbering) forms a thiohemiacetal with BAL, totally blocking the productive binding of the aldehyde. It is of interest that, in contrast to Cys(450), the catalytic cysteine (Cys(291)) did not react with BAL in the absence of NAD(+) The trimethylammonium group of BAL binds in the same position in the inactivating or productive modes. Accordingly, BAL does not inactivate the C(450)SSoBADH mutant and the degree of inactivation of the A(441)I and A(441)C mutants corresponds to their very different abilities to bind the trimethylammonium group. Cys(450)and the neighbouring residues that participate in stabilizing the thiohemiacetal are strictly conserved in plant ALDH10 enzymes with proven or predicted BADH activity, suggesting that inactivation by BAL is their common feature. Under osmotic stress conditions, this novel partial and reversible covalent regulatory mechanism may contribute to preventing NAD(+)exhaustion, while still permitting the synthesis of high amounts of GB and avoiding the accumulation of the toxic BAL.

  4. Possible role of alteration of aldehyde's scavenger enzymes during aging.

    PubMed

    Davydov, Vadim V; Dobaeva, Nataly M; Bozhkov, Anatoly I

    2004-01-01

    Apoptosis in tissues is induced by different kind of signals including endogenous aldehydes, such as 4-hydroxy-2, 3-nonenal. The accumulation rate of aldehydes in the cell is affected by conditions of oxidative stress. In the cell, aldehydes can be metabolized by various isoforms of aldehyde dehydrogenase, aldehyde reductase, and glutathione-S-transferase. There is evidence suggesting that the catalytic properties of these enzymes change during ontogenesis, and that aging is accompanied by their reduced activities. These functional changes may contribute substantially to the alteration in the organism sensitivity to damaging action of stress factors during aging, to age-related modulation of the action of endogenous aldehydes as a signal for apoptosis, and finally, to the origin of diseases associated with aging. In this context, the stimulation of enzymes' expression, and the activation of the catalytic properties of enzymes responsible for catabolism of endogenous aldehydes could become a perspective direction in increasing the organism resistance to the action of damaging factors during aging.

  5. Tandem affinity purification to identify cytosolic and nuclear gβγ-interacting proteins.

    PubMed

    Campden, Rhiannon; Pétrin, Darlaine; Robitaille, Mélanie; Audet, Nicolas; Gora, Sarah; Angers, Stéphane; Hébert, Terence E

    2015-01-01

    It has become clear in recent years that the Gβγ subunits of heterotrimeric proteins serve broad roles in the regulation of cellular activity and interact with many proteins in different subcellular locations including the nucleus. Protein affinity purification is a common method to identify and confirm protein interactions. When used in conjugation with mass spectrometry it can be used to identify novel protein interactions with a given bait protein. The tandem affinity purification (TAP) technique identifies partner proteins bound to tagged protein bait. Combined with protocols to enrich the nuclear fraction of whole cell lysate through sucrose cushions, TAP allows for purification of interacting proteins found specifically in the nucleus. Here we describe the use of the TAP technique on cytosolic and nuclear lysates to identify candidate proteins, through mass spectrometry, that bind to Gβ1 subunits.

  6. Quantitative assessment of cytosolic Salmonella in epithelial cells.

    PubMed

    Knodler, Leigh A; Nair, Vinod; Steele-Mortimer, Olivia

    2014-01-01

    Within mammalian cells, Salmonella enterica serovar Typhimurium (S. Typhimurium) inhabits a membrane-bound vacuole known as the Salmonella-containing vacuole (SCV). We have recently shown that wild type S. Typhimurium also colonizes the cytosol of epithelial cells. Here we sought to quantify the contribution of cytosolic Salmonella to the total population over a time course of infection in different epithelial cell lines and under conditions of altered vacuolar escape. We found that the lysosomotropic agent, chloroquine, acts on vacuolar, but not cytosolic, Salmonella. After chloroquine treatment, vacuolar bacteria are not transcriptionally active or replicative and appear degraded. Using a chloroquine resistance assay, in addition to digitonin permeabilization, we found that S. Typhimurium lyses its nascent vacuole in numerous epithelial cell lines, albeit with different frequencies, and hyper-replication in the cytosol is also widespread. At later times post-infection, cytosolic bacteria account for half of the total population in some epithelial cell lines, namely HeLa and Caco-2 C2Bbe1. Both techniques accurately measured increased vacuole lysis in epithelial cells upon treatment with wortmannin. By chloroquine resistance assay, we also determined that Salmonella pathogenicity island-1 (SPI-1), but not SPI-2, the virulence plasmid nor the flagellar apparatus, was required for vacuolar escape and cytosolic replication in epithelial cells. Together, digitonin permeabilization and the chloroquine resistance assay will be useful, complementary tools for deciphering the mechanisms of SCV lysis and Salmonella replication in the epithelial cell cytosol.

  7. Mechanism and evolution of cytosolic Hedgehog signal transduction

    PubMed Central

    Wilson, Christopher W.; Chuang, Pao-Tien

    2010-01-01

    Hedgehog (Hh) signaling is required for embryonic patterning and postnatal physiology in invertebrates and vertebrates. With the revelation that the primary cilium is crucial for mammalian Hh signaling, the prevailing view that Hh signal transduction mechanisms are conserved across species has been challenged. However, more recent progress on elucidating the function of core Hh pathway cytosolic regulators in Drosophila, zebrafish and mice has confirmed that the essential logic of Hh transduction is similar between species. Here, we review Hh signaling events at the membrane and in the cytosol, and focus on parallel and divergent functions of cytosolic Hh regulators in Drosophila and mammals. PMID:20530542

  8. A Novel Reaction Mediated by Human Aldehyde Oxidase: Amide Hydrolysis of GDC-0834

    PubMed Central

    Wong, Susan; Kirkpatrick, Donald S.; Liu, Lichuan; Khojasteh, S. Cyrus; Hop, Cornelis E. C. A.; Barr, John T.; Jones, Jeffrey P.; Halladay, Jason S.

    2015-01-01

    GDC-0834, a Bruton’s tyrosine kinase inhibitor investigated as a potential treatment of rheumatoid arthritis, was previously reported to be extensively metabolized by amide hydrolysis such that no measurable levels of this compound were detected in human circulation after oral administration. In vitro studies in human liver cytosol determined that GDC-0834 (R)-N-(3-(6-(4-(1,4-dimethyl-3-oxopiperazin-2-yl)phenylamino)-4-methyl-5-oxo- 4,5-dihydropyrazin-2-yl)-2-methylphenyl)-4,5,6,7-tetrahydrobenzo[b] thiophene-2-carboxamide) was rapidly hydrolyzed with a CLint of 0.511 ml/min per milligram of protein. Aldehyde oxidase (AO) and carboxylesterase (CES) were putatively identified as the enzymes responsible after cytosolic fractionation and mass spectrometry-proteomics analysis of the enzymatically active fractions. Results were confirmed by a series of kinetic experiments with inhibitors of AO, CES, and xanthine oxidase (XO), which implicated AO and CES, but not XO, as mediating GDC-0834 amide hydrolysis. Further supporting the interaction between GDC-0834 and AO, GDC-0834 was shown to be a potent reversible inhibitor of six known AO substrates with IC50 values ranging from 0.86 to 1.87 μM. Additionally, in silico modeling studies suggest that GDC-0834 is capable of binding in the active site of AO with the amide bond of GDC-0834 near the molybdenum cofactor (MoCo), orientated in such a way to enable potential nucleophilic attack on the carbonyl of the amide bond by the hydroxyl of MoCo. Together, the in vitro and in silico results suggest the involvement of AO in the amide hydrolysis of GDC-0834. PMID:25845827

  9. 27 CFR 24.183 - Use of distillates containing aldehydes.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... the fermentation of wine and then returned to the distilled spirits plant from which distillates were... fermentation of wine made from a different kind of fruit. Distillates containing aldehydes which are...

  10. 27 CFR 24.183 - Use of distillates containing aldehydes.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... the fermentation of wine and then returned to the distilled spirits plant from which distillates were... fermentation of wine made from a different kind of fruit. Distillates containing aldehydes which are...

  11. 27 CFR 24.183 - Use of distillates containing aldehydes.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... the fermentation of wine and then returned to the distilled spirits plant from which distillates were... fermentation of wine made from a different kind of fruit. Distillates containing aldehydes which are...

  12. 27 CFR 24.183 - Use of distillates containing aldehydes.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... the fermentation of wine and then returned to the distilled spirits plant from which distillates were... fermentation of wine made from a different kind of fruit. Distillates containing aldehydes which are...

  13. 27 CFR 24.183 - Use of distillates containing aldehydes.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... the fermentation of wine and then returned to the distilled spirits plant from which distillates were... fermentation of wine made from a different kind of fruit. Distillates containing aldehydes which are...

  14. Molecular Structure and Reactivity in the Pyrolysis of Aldehydes

    NASA Astrophysics Data System (ADS)

    Sias, Eric; Cole, Sarah; Sowards, John; Warner, Brian; Wright, Emily; McCunn, Laura R.

    2016-06-01

    The effect of alkyl chain structure on pyrolysis mechanisms has been investigated in a series of aldehydes. Isovaleraldehyde, CH_3CH(CH_3)CH_2CHO, and pivaldehyde, (CH_3)_3CCHO, were subject to thermal decomposition in a resistively heated SiC tubular reactor at 800-1200 °C. Matrix-isolation FTIR spectroscopy was used to identify pyrolysis products. Carbon monoxide and isobutene were major products from each of the aldehydes, which is consistent with what is known from previous studies of unbranched alkyl-chain aldehydes. Other products observed include vinyl alcohol, propene, acetylene, and ethylene, revealing complexities to be considered in the pyrolysis of large, branched-chain aldehydes.

  15. Silver-catalyzed synthesis of amides from amines and aldehydes

    DOEpatents

    Madix, Robert J; Zhou, Ling; Xu, Bingjun; Friend, Cynthia M; Freyschlag, Cassandra G

    2014-11-18

    The invention provides a method for producing amides via the reaction of aldehydes and amines with oxygen adsorbed on a metallic silver or silver alloy catalyst. An exemplary reaction is shown in Scheme 1: (I), (II), (III). ##STR00001##

  16. Cytosolic Innate Immune Sensing and Signaling upon Infection

    PubMed Central

    Radoshevich, Lilliana; Dussurget, Olivier

    2016-01-01

    Cytosolic sensing of pathogens is essential to a productive immune response. Recent reports have emphasized the importance of signaling platforms emanating from organelles and cytosolic sensors, particularly during the response to intracellular pathogens. Here, we highlight recent discoveries identifying the key mediators of nucleic acid and cyclic nucleotide sensing and discuss their importance in host defense. This review will also cover strategies evolved by pathogens to manipulate these pathways. PMID:27014235

  17. Clicking Hydrazine and Aldehyde: The Way to Labeling of Viruses with Quantum Dots.

    PubMed

    Hong, Zheng-Yuan; Lv, Cheng; Liu, An-An; Liu, Shu-Lin; Sun, En-Ze; Zhang, Zhi-Ling; Lei, Ai-Wen; Pang, Dai-Wen

    2015-12-22

    Real-time tracking of fluorophore-tagged viruses in living cells can help uncover virus infection mechanisms. Certainly, the indispensable prerequisite for virus-tracking is to label viruses with some bright and photostable beacons such as quantum dots (QDs) via an appropriate labeling strategy. Herein, we devise a convenient hydrazine-aldehyde based strategy to label viruses with QDs through the conjugation of 4-formylbenzoate (4FB) modified QDs to 6-hydrazinonicotinate acetone hydrazone (HyNic) modified viruses under mild conditions. On the basis of this strategy, viruses can be successfully labeled with QDs with high selectivity, stable conjugation, good reproducibility, high labeling efficiency of 92-93% and maximum retention of both fluorescence properties of QDs and infectivity of viruses, which is very meaningful to tracking and statistical analysis of virus infection processes. By further comparing with the most widely used labeling strategy based on the Biotin-SA system, this new strategy has advantages of both high labeling efficiency and good retention of virus infectivity, thus offering a promising alternative for virus-labeling. Moreover, due to the ubiquitous presence of exposed amino groups on the surface of various viruses, this selective, efficient, reproducible and biofriendly strategy should have good universality for labeling both enveloped and nonenveloped viruses.

  18. Cytochrome P450 3A Conjugation to Ubiquitin in a Process Distinct from Classical Ubiquitination Pathway

    SciTech Connect

    Zangar, Richard C. ); Kimzey, Amy L.; Okita, Janice R.; Wunschel, David S. ); Edwards, Robert J.; Kim, Hyesook; Okita, Richard T.

    2001-12-01

    We characterize a novel microsome system that forms high-molecular-mass (HMM) CYP3A, CYP2E1, and ubiquitin conjugates, but does not alter CYP4A or most other microsomal proteins. The formation of the HMM bands was observed in hepatic microsomes isolated from rats treated 1 week or more with high doses (50 mg/kg/day) of nicardipine, clotrimazole, or pregnenolone 16alpha-carbonitrile, but not microsomes from control, dexamethasone-, nifedipine-, or diltiazem-treated rats. Extensive washing of the microsomes to remove loosely attached proteins or cytosolic contaminants did not prevent the conjugation reaction. In contrast to prototypical ubiquitination pathways, this reaction did not require addition of ubiquitin, ATP, Mg(2+), or cytosol. Addition of cytosol did result in the degradation of the HMM CYP3A bands in a process that was not blocked by proteasome inhibitors. Immunoprecipitated CYP3A contained HMM ubiquitin. Even so, mass spectrometric analysis of tryptic peptides indicated that the HMM CYP3A was in molar excess to ubiquitin, suggesting that the formation of the HMM CYP3A may have resulted from conjugation to itself or a diffuse pool of ubiquitinated proteins already present in the microsomes. Addition of CYP3A substrates inhibited the formation of the HMM CYP3A and the cytosol-dependent degradation of HMM CYP3A. These results suggest that after extended periods of elevated CYP3A expression, microsomal factors are induced that catalyze the formation of HMM CYP3A conjugates that contain ubiquitin. This conjugation reaction, however, seems to be distinct from the classical ubiquitination pathway but may be related to the substrate-dependent stabilization of CYP3A observed in vivo.

  19. Functional and expression analyses of two kinds of betaine aldehyde dehydrogenases in a glycinebetaine-hyperaccumulating graminaceous halophyte, Leymus chinensis.

    PubMed

    Mitsuya, Shiro; Tsuchiya, Asumi; Kono-Ozaki, Keiko; Fujiwara, Takashi; Takabe, Teruhiro; Takabe, Tetsuko

    2015-01-01

    Glycinebetaine (GB) is an important compatible solute for salinity tolerance in many plants. In this study, we analyzed the enzymatic activity and the expression level of betaine aldehyde dehydrogenase (BADH), an important enzyme that catalyzes the last step in the GB synthesis in Leymus chinensis, a GB-hyperaccumulating graminaceous halophyte, and compared with those of barley, a graminaceous glycophyte. We have isolated cDNAs for two BADH genes, LcBADH1 and LcBADH2. LcBADH1 has a putative peroxisomal signal peptide (PTS1) at its C-terminus, while LcBADH2 does not have any typical signal peptide. Using immunofluorescent labeling, we showed that BADH proteins were localized to the cytosol and dot-shaped organelles in the mesophyll and bundle sheath cells of L.chinensis leaves. The affinity of recombinant LcBADH2 for betaine aldehyde was comparable to other plant BADHs, whereas recombinant LcBADH1 showed extremely low affinity for betaine aldehyde, indicating that LcBADH2 plays a major role in GB synthesis in L. chinensis. In addition, the recombinant LcBADH2 protein was tolerant to NaCl whereas LcBADH1 wasn't. The kinetics, subcellular and tissue localization of BADH proteins were comparable between L. chinensis and barley. The activity and expression level of BADH proteins were higher in L. chinensis compared with barley under both normal and salinized conditions, which may be related to the significant difference in the amount of GB accumulation between two plants.

  20. Cytosolic triacylglycerol biosynthetic pathway in oilseeds. Molecular cloning and expression of peanut cytosolic diacylglycerol acyltransferase.

    PubMed

    Saha, Saikat; Enugutti, Balaji; Rajakumari, Sona; Rajasekharan, Ram

    2006-08-01

    Triacylglycerols (TAGs) are the most important storage form of energy for eukaryotic cells. TAG biosynthetic activity was identified in the cytosolic fraction of developing peanut (Arachis hypogaea) cotyledons. This activity was NaF insensitive and acyl-coenzyme A (CoA) dependent. Acyl-CoA:diacylglycerol acyltransferase (DGAT) catalyzes the final step in TAG biosynthesis that acylates diacylglycerol to TAG. Soluble DGAT was identified from immature peanuts and purified by conventional column chromatographic procedures. The enzyme has a molecular mass of 41 +/- 1.0 kD. Based on the partial peptide sequence, a degenerate probe was used to obtain the full-length cDNA. The isolated gene shared less than 10% identity with the previously identified DGAT1 and 2 families, but has 13% identity with the bacterial bifunctional wax ester/DGAT. To differentiate the unrelated families, we designate the peanut gene as AhDGAT. Expression of peanut cDNA in Escherichia coli resulted in the formation of labeled TAG and wax ester from [14C]acetate. The recombinant E. coli showed high levels of DGAT activity but no wax ester synthase activity. TAGs were localized in transformed cells with Nile blue A and oil red O staining. The recombinant and native DGAT was specific for 1,2-diacylglycerol and did not utilize hexadecanol, glycerol-3-phosphate, monoacylglycerol, lysophosphatidic acid, and lysophosphatidylcholine. Oleoyl-CoA was the preferred acyl donor as compared to palmitoyl- and stearoyl-CoAs. These data suggest that the cytosol is one of the sites for TAG biosynthesis in oilseeds. The identified pathway may present opportunities of bioengineering oil-yielding plants for increased oil production.

  1. Interspecies differences in the metabolism of methotrexate: An insight into the active site differences between human and rabbit aldehyde oxidase.

    PubMed

    Choughule, Kanika V; Joswig-Jones, Carolyn A; Jones, Jeffrey P

    2015-08-01

    Several drug compounds have failed in clinical trials due to extensive biotransformation by aldehyde oxidase (AOX) (EC 1.2.3.1). One of the main reasons is the difficulty in scaling clearance for drugs metabolised by AOX, from preclinical species to human. Using methotrexate as a probe substrate, we evaluated AOX metabolism in liver cytosol from human and commonly used laboratory species namely guinea pig, monkey, rat and rabbit. We found that the metabolism of methotrexate in rabbit liver cytosol was several orders of magnitude higher than any of the other species tested. The results of protein quantitation revealed that the amount of AOX1 in human liver was similar to rabbit liver. To understand if the observed differences in activity were due to structural differences, we modelled rabbit AOX1 using the previously generated human AOX1 homology model. Molecular docking of methotrexate into the active site of the enzyme led to the identification of important residues that could potentially be involved in substrate binding and account for the observed differences. In order to study the impact of these residue changes on enzyme activity, we used site directed mutagenesis to construct mutant AOX1 cDNAs by substituting nucleotides of human AOX1 with relevant ones of rabbit AOX1. AOX1 mutant proteins were expressed in Escherichia coli. Differences in the kinetic properties of these mutants have been presented in this study.

  2. Multiple cytosolic calcium buffers in posterior pituitary nerve terminals.

    PubMed

    McMahon, Shane M; Chang, Che-Wei; Jackson, Meyer B

    2016-03-01

    Cytosolic Ca(2+) buffers bind to a large fraction of Ca(2+) as it enters a cell, shaping Ca(2+) signals both spatially and temporally. In this way, cytosolic Ca(2+) buffers regulate excitation-secretion coupling and short-term plasticity of release. The posterior pituitary is composed of peptidergic nerve terminals, which release oxytocin and vasopressin in response to Ca(2+) entry. Secretion of these hormones exhibits a complex dependence on the frequency and pattern of electrical activity, and the role of cytosolic Ca(2+) buffers in controlling pituitary Ca(2+) signaling is poorly understood. Here, cytosolic Ca(2+) buffers were studied with two-photon imaging in patch-clamped nerve terminals of the rat posterior pituitary. Fluorescence of the Ca(2+) indicator fluo-8 revealed stepwise increases in free Ca(2+) after a series of brief depolarizing pulses in rapid succession. These Ca(2+) increments grew larger as free Ca(2+) rose to saturate the cytosolic buffers and reduce the availability of Ca(2+) binding sites. These titration data revealed two endogenous buffers. All nerve terminals contained a buffer with a Kd of 1.5-4.7 µM, and approximately half contained an additional higher-affinity buffer with a Kd of 340 nM. Western blots identified calretinin and calbindin D28K in the posterior pituitary, and their in vitro binding properties correspond well with our fluorometric analysis. The high-affinity buffer washed out, but at a rate much slower than expected from diffusion; washout of the low-affinity buffer could not be detected. This work has revealed the functional impact of cytosolic Ca(2+) buffers in situ in nerve terminals at a new level of detail. The saturation of these cytosolic buffers will amplify Ca(2+) signals and may contribute to use-dependent facilitation of release. A difference in the buffer compositions of oxytocin and vasopressin nerve terminals could contribute to the differences in release plasticity of these two hormones.

  3. Conjugal amyotrophic lateral sclerosis

    PubMed Central

    Dewitt, John D.; Kwon, Julia; Burton, Rebecca

    2012-01-01

    Amyotrophic lateral sclerosis (ALS) is a disease characterized by progressive degeneration of motor neurons in the motor cortex, brainstem, and spinal cord. The incidence of sporadic ALS is 1.5 to 2.7 in 100,000, and the prevalence is 5.2 to 6.0 in 100,000. Conjugal ALS is even rarer than sporadic ALS. We report a case of conjugal ALS encountered in our outpatient neurology clinic. PMID:22275781

  4. Drosophila melanogaster alcohol dehydrogenase: mechanism of aldehyde oxidation and dismutation.

    PubMed

    Winberg, J O; McKinley-McKee, J S

    1998-02-01

    Drosophila alcohol dehydrogenase (Adh) catalyses the oxidation of both alcohols and aldehydes. In the latter case, the oxidation is followed by a reduction of the aldehyde, i.e. a dismutation reaction. At high pH, dismutation is accompanied by a small release of NADH, which is not observed at neutral pH. Previously it has been emphasized that kinetic coefficients obtained by measuring the increase in A340, i.e. the release of NADH at high pH is not a direct measure of the aldehyde oxidation reaction and these values cannot be compared with those for alcohol dehydrogenation. In this article we demonstrate that this is not entirely true, and that the coefficients phiB and phiAB, where B is the aldehyde and A is NAD+, are the same for a dismutation reaction and a simple aldehyde dehydrogenase reaction. Thus the substrate specificity of the aldehyde oxidation reaction can be determined by simply measuring the NADH release. The coefficients for oxidation and dehydrogenation reactions (phi0d and phiAd respectively) are complex and involve the constants for the dismutation reaction. However, dead-end inhibitors can be used to determine the quantitative contribution of the kinetic constants for the aldehyde oxidation and reduction pathways to the phi0d and phiAd coefficients. The combination of dead-end and product inhibitors can be used to determine the reaction mechanism for the aldehyde oxidation pathway. Previously, we showed that with Drosophila Adh, the interconversion between alcohols and aldehydes followed a strictly compulsory ordered pathway, although aldehydes and ketones formed binary complexes with the enzyme. This raised the question regarding the reaction mechanism for the oxidation of aldehydes, i.e. whether a random ordered pathway was followed. In the present work, the mechanism for the oxidation of different aldehydes and the accompanying dismutation reaction with the slow alleloenzyme (AdhS) from Drosophila melanogaster has been studied. To obtain

  5. Drosophila melanogaster alcohol dehydrogenase: mechanism of aldehyde oxidation and dismutation.

    PubMed Central

    Winberg, J O; McKinley-McKee, J S

    1998-01-01

    Drosophila alcohol dehydrogenase (Adh) catalyses the oxidation of both alcohols and aldehydes. In the latter case, the oxidation is followed by a reduction of the aldehyde, i.e. a dismutation reaction. At high pH, dismutation is accompanied by a small release of NADH, which is not observed at neutral pH. Previously it has been emphasized that kinetic coefficients obtained by measuring the increase in A340, i.e. the release of NADH at high pH is not a direct measure of the aldehyde oxidation reaction and these values cannot be compared with those for alcohol dehydrogenation. In this article we demonstrate that this is not entirely true, and that the coefficients phiB and phiAB, where B is the aldehyde and A is NAD+, are the same for a dismutation reaction and a simple aldehyde dehydrogenase reaction. Thus the substrate specificity of the aldehyde oxidation reaction can be determined by simply measuring the NADH release. The coefficients for oxidation and dehydrogenation reactions (phi0d and phiAd respectively) are complex and involve the constants for the dismutation reaction. However, dead-end inhibitors can be used to determine the quantitative contribution of the kinetic constants for the aldehyde oxidation and reduction pathways to the phi0d and phiAd coefficients. The combination of dead-end and product inhibitors can be used to determine the reaction mechanism for the aldehyde oxidation pathway. Previously, we showed that with Drosophila Adh, the interconversion between alcohols and aldehydes followed a strictly compulsory ordered pathway, although aldehydes and ketones formed binary complexes with the enzyme. This raised the question regarding the reaction mechanism for the oxidation of aldehydes, i.e. whether a random ordered pathway was followed. In the present work, the mechanism for the oxidation of different aldehydes and the accompanying dismutation reaction with the slow alleloenzyme (AdhS) from Drosophila melanogaster has been studied. To obtain

  6. Development of indirect competitive fluorescence immunoassay for 2,2',4,4'-tetrabromodiphenyl ether using DNA/dye conjugate as antibody multiple labels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An indirect competitive fluorescence immunoassay using DNA/dye conjugate as antibody multiple labels was developed on 96-well plates for the identification and quantification of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) in aqueous samples. A hapten, 2,4,2'-tribromodiphenyl ether-4’-aldehyde was sy...

  7. Contribution of ozone to airborne aldehyde formation in Paris homes.

    PubMed

    Rancière, Fanny; Dassonville, Claire; Roda, Célina; Laurent, Anne-Marie; Le Moullec, Yvon; Momas, Isabelle

    2011-09-15

    Indoor aldehydes may result from ozone-initiated chemistry, mainly documented by experimental studies. As part of an environmental investigation included in the PARIS birth cohort, the aim of this study was to examine ozone contribution to airborne aldehyde formation in Paris homes. Formaldehyde, acetaldehyde and hexaldehyde levels, as well as styrene, nitrogen dioxide and nicotine concentrations, comfort parameters and carbon dioxide levels, were measured twice during the first year of life of the babies. Ambient ozone concentrations were collected from the closest background station of the regional air monitoring network. Traffic-related nitrogen oxide concentrations in front of the dwellings were estimated by an air pollution dispersion model. Home characteristics and families' way of life were described by questionnaires. Stepwise multiple linear regression models were used to link aldehyde levels with ambient ozone concentrations and a few aldehyde precursors involved in oxidation reactions, adjusting for other indoor aldehyde sources, comfort parameters and traffic-related nitrogen oxides. A 4 and 11% increase in formaldehyde and hexaldehyde levels was pointed out when 8-hour ozone concentrations increased by 20 μg/m(3). The influence of potential precursors such as indoor styrene level and frequent use of air fresheners, containing unsaturated volatile organic compounds as terpenes, was also found. Thus, our results suggest that ambient ozone can significantly impact indoor air quality, especially with regard to formaldehyde and hexaldehyde levels.

  8. Kinetic properties of aldehyde dehydrogenase from sheep liver mitochondria.

    PubMed Central

    Hart, G J; Dickinson, F M

    1978-01-01

    The kinetics of the NAD+-dependent oxidation of aldehydes, catalysed by aldehyde dehydrogenase purified from sheep liver mitochondria, were studied in detail. Lag phases were observed in the assays, the length of which were dependent on the enzyme concentration. The measured rates after the lag phase was over were directly proportional to the enzyme concentration. If enzyme was preincubated with NAD+, the lag phase was eliminated. Double-reciprocal plots with aldehyde as the variable substrate were non-linear, showing marked substrate activation. With NAD+ as the variable substrate, double-reciprocal plots were linear, and apparently parallel. Double-reciprocal plots with enzyme modified with disulfiram (tetraethylthiuram disulphide) or iodoacetamide, such that at pH 8.0 the activity was decreased to 50% of the control value, showed no substrate activation, and the plots were linear. At pH 7.0, the kinetic parameters Vmax. and Km NAD+- for the oxidation of acetaldehyde and butyraldehyde by the native enzyme are almost identical. Formaldehyde and propionaldehyde show the same apparent maximum rate. Aldehyde dehydrogenase is able to catalyse the hydrolysis of p-nitrophenyl esters. This esterase activity was stimulated by both NAD+ and NADH, the maximum rate for the NAD+ stimulated esterase reaction being roughly equal to the maximum rate for the oxidation of aldehydes. The mechanistic implications of the above behaviour are discussed. PMID:217355

  9. Formation of C═C bond via knoevenagel reaction between aromatic aldehyde and barbituric acid at liquid/HOPG and vapor/HOPG interfaces.

    PubMed

    Geng, Yanfang; Dai, Hongliang; Chang, Shaoqing; Hu, Fangyun; Zeng, Qingdao; Wang, Chen

    2015-03-01

    Controlling chemical reactions on surface is of great importance to constructing self-assembled covalent nanostructures. Herein, Knoevenagel reaction between aromatic aldehyde compound 2,5-di(5-aldehyde-2-thienyl)-1,4-dioctyloxybenzene (PT2) and barbituric acid (BA) has been successfully performed for the first time at liquid/HOPG interface and vapor/HOPG interface. The resulting surface nanostructures and the formation of C═C bond are recorded through scanning tunneling microscopy (STM), and confirmed by attenuated total reflectance Fourier-transform infrared (ATR/FT-IR) spectrometer and UV-vis absorption. The obtained results reveal that Knoevenagel condensation reaction can efficiently occur at both interfaces. This surface reaction would be an important step toward further reaction to produce innovative conjugated nanomaterial on the surface.

  10. Concerted action of the cytosolic sulfotransferase, SULT1A3, and catechol-O-methyltransferase in the metabolism of dopamine in SK-N-MC human neuroblastoma cells.

    PubMed

    Yasuda, Shin; Yasuda, Tomoko; Hui, Ying; Liu, Ming-Yih; Suiko, Masahito; Sakakibara, Yoichi; Liu, Ming-Cheh

    2009-07-01

    Conjugation reactions catalyzed by the cytosolic sulfotransferase, SULT1A3, or catechol-O-methyltransferase (COMT) are known to be involved in the regulation and homeostasis of dopamine and other monoamine neurotransmitters. Whether different conjugation reactions may act in a concerted manner, however, remains unclear. The current study aimed to investigate the concerted action of SULT1A3 and COMT in dopamine metabolism. Analysis of the medium of SK-N-MC cells, metabolically labeled with [(35)S]sulfate in the presence of dopamine, revealed the generation and release of predominantly [(35)S]sulfated 3-methyldopamine and, to a lesser extent [(35)S]sulfated dopamine. Addition to the labeling medium of tropolone, a COMT inhibitor, enhanced the production of [(35)S]sulfated dopamine, with a concomitant decrease of [(35)S]sulfated 3-methyldopamine. Enzymatic assays using the eleven known human cytosolic SULTs revealed SULT1A3 as the major enzyme responsible for the sulfation of both dopamine and 3-methyldopamine. Kinetic analysis showed that the catalytic efficiency of SULT1A3 with 3-methyldopamine was 1.6 times than that with dopamine. Using subcellular fractions prepared from SK-N-MC cells, the majority of COMT dopamine-methylating activity was found to be present in the cytosol. Collectively, these results imply a concerted action of sulfation and methylation in the irreversible inactivation and disposal of excess dopamine in SK-N-MC cells.

  11. The Arabidopsis Cytosolic Ribosomal Proteome: From form to Function

    PubMed Central

    Carroll, Adam J.

    2013-01-01

    The cytosolic ribosomal proteome of Arabidopsis thaliana has been studied intensively by a range of proteomics approaches and is now one of the most well characterized eukaryotic ribosomal proteomes. Plant cytosolic ribosomes are distinguished from other eukaryotic ribosomes by unique proteins, unique post-translational modifications and an abundance of ribosomal proteins for which multiple divergent paralogs are expressed and incorporated. Study of the A. thaliana ribosome has now progressed well beyond a simple cataloging of protein parts and is focused strongly on elucidating the functions of specific ribosomal proteins, their paralogous isoforms and covalent modifications. This review summarises current knowledge concerning the Arabidopsis cytosolic ribosomal proteome and highlights potentially fruitful areas of future research in this fast moving and important area. PMID:23459595

  12. Lipid Biosynthesis Coordinates a Mitochondrial-to-Cytosolic Stress Response.

    PubMed

    Kim, Hyun-Eui; Grant, Ana Rodrigues; Simic, Milos S; Kohnz, Rebecca A; Nomura, Daniel K; Durieux, Jenni; Riera, Celine E; Sanchez, Melissa; Kapernick, Erik; Wolff, Suzanne; Dillin, Andrew

    2016-09-01

    Defects in mitochondrial metabolism have been increasingly linked with age-onset protein-misfolding diseases such as Alzheimer's, Parkinson's, and Huntington's. In response to protein-folding stress, compartment-specific unfolded protein responses (UPRs) within the ER, mitochondria, and cytosol work in parallel to ensure cellular protein homeostasis. While perturbation of individual compartments can make other compartments more susceptible to protein stress, the cellular conditions that trigger cross-communication between the individual UPRs remain poorly understood. We have uncovered a conserved, robust mechanism linking mitochondrial protein homeostasis and the cytosolic folding environment through changes in lipid homeostasis. Metabolic restructuring caused by mitochondrial stress or small-molecule activators trigger changes in gene expression coordinated uniquely by both the mitochondrial and cytosolic UPRs, protecting the cell from disease-associated proteins. Our data suggest an intricate and unique system of communication between UPRs in response to metabolic changes that could unveil new targets for diseases of protein misfolding. PMID:27610574

  13. Maternal aldehyde elimination during pregnancy preserves the fetal genome.

    PubMed

    Oberbeck, Nina; Langevin, Frédéric; King, Gareth; de Wind, Niels; Crossan, Gerry P; Patel, Ketan J

    2014-09-18

    Maternal metabolism provides essential nutrients to enable embryonic development. However, both mother and embryo produce reactive metabolites that can damage DNA. Here we discover how the embryo is protected from these genotoxins. Pregnant mice lacking Aldh2, a key enzyme that detoxifies reactive aldehydes, cannot support the development of embryos lacking the Fanconi anemia DNA repair pathway gene Fanca. Remarkably, transferring Aldh2(-/-)Fanca(-/-) embryos into wild-type mothers suppresses developmental defects and rescues embryonic lethality. These rescued neonates have severely depleted hematopoietic stem and progenitor cells, indicating that despite intact maternal aldehyde catabolism, fetal Aldh2 is essential for hematopoiesis. Hence, maternal and fetal aldehyde detoxification protects the developing embryo from DNA damage. Failure of this genome preservation mechanism might explain why birth defects and bone marrow failure occur in Fanconi anemia, and may have implications for fetal well-being in the many women in Southeast Asia that are genetically deficient in ALDH2. PMID:25155611

  14. Polyvinyl alcohol cross-linked with two aldehydes

    NASA Technical Reports Server (NTRS)

    Sheibley, D. W.; Rieker, L. L.; Hsu, L. C.; Manzo, M. A. (Inventor)

    1982-01-01

    A film forming polyvinyl alcohol resin is admixed, in aqueous solution, with a dialdehyde crosslinking agent which is capable of crosslinking the polyvinyl alcohol resin and a water soluble acid aldehyde containing a reactive aldehyde group capable of reacting with hydroxyl groups in the polyvinyl alcohol resin and an ionizable acid hydrogen atom. The dialdehyde is present in an amount sufficient to react with from 1 to 20% by weight of the theoretical amount required to react with all of the hydroxyl groups of the polyvinyl alcohol. The amount of acid aldehyde is from 1 to 50% by weight, same basis, and is sufficient to reduce the pH of the aqueous admixture to 5 or less. The admixture is then formed into a desired physical shape, such as by casting a sheet or film, and the shaped material is then heated to simultaneously dry and crosslink the article.

  15. RP-HPLC-fluorescence analysis of aliphatic aldehydes: application to aldehyde-generating enzymes HACL1 and SGPL1.

    PubMed

    Mezzar, Serena; de Schryver, Evelyn; Van Veldhoven, Paul P

    2014-03-01

    Long-chain aldehydes are commonly produced in various processes, such as peroxisomal α-oxidation of long-chain 3-methyl-branched and 2-hydroxy fatty acids and microsomal breakdown of phosphorylated sphingoid bases. The enzymes involved in the aldehyde-generating steps of these processes are 2-hydroxyacyl-CoA lyase (HACL1) and sphingosine-1-phosphate lyase (SGPL1), respectively. In the present work, nonradioactive assays for these enzymes were developed employing the Hantzsch reaction. Tridecanal (C13-al) and heptadecanal (C17-al) were selected as model compounds and cyclohexane-1,3-dione as 1,3-diketone, and the fluorescent derivatives were analyzed by reversed phase (RP)-HPLC. Assay mixture composition, as well as pH and heating, were optimized for C13-al and C17-al. Under optimized conditions, these aldehydes could be quantified in picomolar range and different long-chain aldehyde derivatives were well resolved with a linear gradient elution by RP-HPLC. Aldehydes generated by recombinant enzymes could easily be detected via this method. Moreover, the assay allowed to document activity or deficiency in tissue homogenates and fibroblast lysates without an extraction step. In conclusion, a simple, quick, and cheap assay for the study of HACL1 and SGPL1 activities was developed, without relying on expensive mass spectrometric detectors or radioactive substrates.

  16. Direct β-Alkylation of Aldehydes via Photoredox Organocatalysis

    PubMed Central

    2015-01-01

    Direct β-alkylation of saturated aldehydes has been accomplished by synergistically combining photoredox catalysis and organocatalysis. Photon-induced enamine oxidation provides an activated β-enaminyl radical intermediate, which readily combines with a wide range of Michael acceptors to produce β-alkyl aldehydes in a highly efficient manner. Furthermore, this redox-neutral, atom-economical C–H functionalization protocol can be achieved both inter- and intramolecularly. Mechanistic studies by various spectroscopic methods suggest that a reductive quenching pathway is operable. PMID:24754456

  17. Tunable Ether Production via Coupling of Aldehydes or Aldehyde/Alcohol over Hydrogen-Modified Gold Catalysts at Low Temperatures.

    PubMed

    Pan, Ming; Brush, Adrian J; Dong, Guangbin; Mullins, C Buddie

    2012-09-01

    Ethers are an important group of organic compounds that are primarily prepared via homogeneous catalysis, which can lead to operational and environmental issues. Here we demonstrate the production of ethers via heterogeneous catalysis over H adatom-covered gold at temperatures lower than 250 K. Symmetrical ethers can be formed via a self-coupling reaction of corresponding aldehydes; for example, homocoupling of acetaldehyde and propionaldehyde yields diethyl ether and di-n-propyl ether, respectively. In addition, coupling reactions between alcohols and aldehydes, with different carbon chain lengths, are observed via the production of the corresponding unsymmetrical ethers. A reaction mechanism is proposed, suggesting that an alcohol-like intermediate via partial hydrogenation of aldehydes on the surface plays a key role in these reactions. These surface chemical reactions suggest possible heterogeneous routes to low-temperature production of ethers. PMID:26292142

  18. Aldehydic load and aldehyde dehydrogenase 2 profile during the progression of post-myocardial infarction cardiomyopathy: benefits of Alda-1

    PubMed Central

    Gomes, Katia M.S.; Bechara, Luiz R.G.; Lima, Vanessa M.; Ribeiro, Márcio A.C.; Campos, Juliane C.; Dourado, Paulo M.; Kowaltowski, Alicia J.; Mochly-Rosen, Daria; Ferreira, Julio C.B.

    2015-01-01

    Background/Objectives We previously demonstrated that reducing cardiac aldehydic load by aldehyde dehydrogenase 2 (ALDH2), a mitochondrial enzyme responsible for metabolizing the major lipid peroxidation product, protects against acute ischemia/reperfusion injury and chronic heart failure. However, time-dependent changes in ALDH2 profile, aldehydic load and mitochondrial bioenergetics during progression of post-myocardial infarction (post-MI) cardiomyopathy is unknown and should be established to determine the optimal time window for drug treatment. Methods Here we characterized cardiac ALDH2 activity and expression, lipid peroxidation, 4-hydroxy-2-nonenal (4-HNE) adduct formation, glutathione pool and mitochondrial energy metabolism and H2O2 release during the 4 weeks after permanent left anterior descending (LAD) coronary artery occlusion in rats. Results We observed a sustained disruption of cardiac mitochondrial function during the progression of post-MI cardiomyopathy, characterized by >50% reduced mitochondrial respiratory control ratios and up to 2 fold increase in H2O2 release. Mitochondrial dysfunction was accompanied by accumulation of cardiac and circulating lipid peroxides and 4-HNE protein adducts and down-regulation of electron transport chain complexes I and V. Moreover, increased aldehydic load was associated with a 90% reduction in cardiac ALDH2 activity and increased glutathione pool. Further supporting an ALDH2 mechanism, sustained Alda-1 treatment (starting 24hrs after permanent LAD occlusion surgery) prevented aldehydic overload, mitochondrial dysfunction and improved ventricular function in post-MI cardiomyopathy rats. Conclusion Taken together, our findings demonstrate a disrupted mitochondrial metabolism along with an insufficient cardiac ALDH2-mediated aldehyde clearance during the progression of ventricular dysfunction, suggesting a potential therapeutic value of ALDH2 activators during the progression of post-myocardial infarction

  19. Applicability of the theory of thermodynamic similarity to predict the enthalpies of vaporization of aliphatic aldehydes

    NASA Astrophysics Data System (ADS)

    Esina, Z. N.; Korchuganova, M. R.

    2015-06-01

    The theory of thermodynamic similarity is used to predict the enthalpies of vaporization of aliphatic aldehydes. The predicted data allow us to calculate the phase diagrams of liquid-vapor equilibrium in a binary water-aliphatic aldehyde system.

  20. The origin of cytosolic ATP in photosynthetic cells.

    PubMed

    Gardeström, Per; Igamberdiev, Abir U

    2016-07-01

    In photosynthetically active cells, both chloroplasts and mitochondria have the capacity to produce ATP via photophosphorylation and oxidative phosphorylation, respectively. Thus, theoretically, both organelles could provide ATP for the cytosol, but the extent, to which they actually do this, and how the process is regulated, both remain unclear. Most of the evidence discussed comes from experiments with rapid fractionation of isolated protoplasts subjected to different treatments in combination with application of specific inhibitors. The results obtained indicate that, under conditions where ATP demand for photosynthetic CO2 fixation is sufficiently high, the mitochondria supply the bulk of ATP for the cytosol. In contrast, under stress conditions where CO2 fixation is severely limited, ATP will build up in chloroplasts and it can then be exported to the cytosol, by metabolite shuttle mechanisms. Thus, depending on the conditions, either mitochondria or chloroplasts can supply the bulk of ATP for the cytosol. This supply of ATP is discussed in relation to the idea that mitochondrial functions may be tuned to provide an optimal environment for the chloroplast. By balancing cellular redox states, mitochondria can contribute to an optimal photosynthetic capacity. PMID:27087668

  1. Shared and Distinct Mechanisms of Compartmentalized and Cytosolic Ciliogenesis.

    PubMed

    Avidor-Reiss, Tomer; Leroux, Michel R

    2015-12-01

    Most motile and all non-motile (also known as primary) eukaryotic cilia possess microtubule-based axonemes that are assembled at the cell surface to form hair-like or more elaborate compartments endowed with motility and/or signaling functions. Such compartmentalized ciliogenesis depends on the core intraflagellar transport (IFT) machinery and the associated Bardet-Biedl syndrome complex (BBSome) for dynamic delivery of ciliary components. The transition zone (TZ), an ultrastructurally complex barrier or 'gate' at the base of cilia, also contributes to the formation of compartmentalized cilia. Yet, some ciliated protists do not have IFT components and, like some metazoan spermatozoa, use IFT-independent mechanisms to build axonemes exposed to the cytosol. Moreover, various ciliated protists lack TZ components, whereas Drosophila sperm surprisingly requires the activity of dynamically localized TZ proteins for cytosolic ciliogenesis. Here, we discuss the various ways eukaryotes use IFT and/or TZ proteins to generate the wide assortment of compartmentalized and cytosolic cilia observed in nature. Consideration of the different ciliogenesis pathways allows us to propose how three types of cytosol-exposed cilia (primary, secondary and tertiary), including cilia found in the human sperm proximal segment, are likely generated by evolutionary derivations of compartmentalized ciliogenesis.

  2. Further progress in cytosolic cellular delivery of quantum dots

    NASA Astrophysics Data System (ADS)

    Boeneman Gemmill, Kelly; Delehanty, James B.; Stewart, Michael H.; Susumu, Kimihiro; Blanco-Canosa, Juan B.; Dawson, Philip E.; Huston, Alan; Medintz, Igor

    2012-03-01

    Currently there is considerable interest in using bioconjugated nanoparticles for in vivo imaging, biosensing and theranostics. Luminescent CdSe/ZnS core shell semiconductor quantum dots (QDs) have unique optical properties and bioconjugation capabilities that make them ideal prototypes for these purposes. We have previously described the metal-affinity association between the imidazole groups of terminal hexahistidine residues of peptides and proteins and the ZnS shell of quantum dots as a useful bioconjugation technique. We have also demonstrated that QDs labeled with an oligohistidine-tagged cell penetrating peptide (CPP) derived from the HIV TAT-protein could undergo specific endocytosis-mediated cellular uptake in both HEK293T/17 and COS-1 cells. However, the QDs were predominantly sequestered in the endosomes. This remains a significant hindrance to future potential cellular imaging applications which require the QDs to access other subcellular organelles. Here we describe the testing of several cytosolic QD delivery modalities including microinjection, the commercial cytosolic delivery agent PULSin, and the cytosolic delivery peptide Palm-1. Palm-1, a palmitylated peptide that is capable of both cellular uptake and rapid endosomal escape in multiple cell lines without concomitant toxicity, is shown to be the superior method for cytosolic delivery of QDs. Potential intracellular applications for this peptide are discussed.

  3. Stabilized polyacrylic saccharide protein conjugates

    DOEpatents

    Callstrom, M.R.; Bednarski, M.D.; Gruber, P.R.

    1996-02-20

    This invention is directed to water soluble protein polymer conjugates which are stable in hostile environments. The conjugate comprises a protein which is linked to an acrylic polymer at multiple points through saccharide linker groups. 16 figs.

  4. Stabilized polyacrylic saccharide protein conjugates

    DOEpatents

    Callstrom, Matthew R.; Bednarski, Mark D.; Gruber, Patrick R.

    1996-01-01

    This invention is directed to water soluble protein polymer conjugates which are stabile in hostile environments. The conjugate comprises a protein which is linked to an acrylic polymer at multiple points through saccharide linker groups.

  5. Multiple cytosolic calcium buffers in posterior pituitary nerve terminals.

    PubMed

    McMahon, Shane M; Chang, Che-Wei; Jackson, Meyer B

    2016-03-01

    Cytosolic Ca(2+) buffers bind to a large fraction of Ca(2+) as it enters a cell, shaping Ca(2+) signals both spatially and temporally. In this way, cytosolic Ca(2+) buffers regulate excitation-secretion coupling and short-term plasticity of release. The posterior pituitary is composed of peptidergic nerve terminals, which release oxytocin and vasopressin in response to Ca(2+) entry. Secretion of these hormones exhibits a complex dependence on the frequency and pattern of electrical activity, and the role of cytosolic Ca(2+) buffers in controlling pituitary Ca(2+) signaling is poorly understood. Here, cytosolic Ca(2+) buffers were studied with two-photon imaging in patch-clamped nerve terminals of the rat posterior pituitary. Fluorescence of the Ca(2+) indicator fluo-8 revealed stepwise increases in free Ca(2+) after a series of brief depolarizing pulses in rapid succession. These Ca(2+) increments grew larger as free Ca(2+) rose to saturate the cytosolic buffers and reduce the availability of Ca(2+) binding sites. These titration data revealed two endogenous buffers. All nerve terminals contained a buffer with a Kd of 1.5-4.7 µM, and approximately half contained an additional higher-affinity buffer with a Kd of 340 nM. Western blots identified calretinin and calbindin D28K in the posterior pituitary, and their in vitro binding properties correspond well with our fluorometric analysis. The high-affinity buffer washed out, but at a rate much slower than expected from diffusion; washout of the low-affinity buffer could not be detected. This work has revealed the functional impact of cytosolic Ca(2+) buffers in situ in nerve terminals at a new level of detail. The saturation of these cytosolic buffers will amplify Ca(2+) signals and may contribute to use-dependent facilitation of release. A difference in the buffer compositions of oxytocin and vasopressin nerve terminals could contribute to the differences in release plasticity of these two hormones. PMID:26880753

  6. Multiple cytosolic calcium buffers in posterior pituitary nerve terminals

    PubMed Central

    McMahon, Shane M.; Chang, Che-Wei

    2016-01-01

    Cytosolic Ca2+ buffers bind to a large fraction of Ca2+ as it enters a cell, shaping Ca2+ signals both spatially and temporally. In this way, cytosolic Ca2+ buffers regulate excitation-secretion coupling and short-term plasticity of release. The posterior pituitary is composed of peptidergic nerve terminals, which release oxytocin and vasopressin in response to Ca2+ entry. Secretion of these hormones exhibits a complex dependence on the frequency and pattern of electrical activity, and the role of cytosolic Ca2+ buffers in controlling pituitary Ca2+ signaling is poorly understood. Here, cytosolic Ca2+ buffers were studied with two-photon imaging in patch-clamped nerve terminals of the rat posterior pituitary. Fluorescence of the Ca2+ indicator fluo-8 revealed stepwise increases in free Ca2+ after a series of brief depolarizing pulses in rapid succession. These Ca2+ increments grew larger as free Ca2+ rose to saturate the cytosolic buffers and reduce the availability of Ca2+ binding sites. These titration data revealed two endogenous buffers. All nerve terminals contained a buffer with a Kd of 1.5–4.7 µM, and approximately half contained an additional higher-affinity buffer with a Kd of 340 nM. Western blots identified calretinin and calbindin D28K in the posterior pituitary, and their in vitro binding properties correspond well with our fluorometric analysis. The high-affinity buffer washed out, but at a rate much slower than expected from diffusion; washout of the low-affinity buffer could not be detected. This work has revealed the functional impact of cytosolic Ca2+ buffers in situ in nerve terminals at a new level of detail. The saturation of these cytosolic buffers will amplify Ca2+ signals and may contribute to use-dependent facilitation of release. A difference in the buffer compositions of oxytocin and vasopressin nerve terminals could contribute to the differences in release plasticity of these two hormones. PMID:26880753

  7. NHC-catalysed highly selective aerobic oxidation of nonactivated aldehydes

    PubMed Central

    Möhlmann, Lennart; Ludwig, Stefan

    2013-01-01

    Summary This publication describes a highly selective oxidation of aldehydes to the corresponding acids or esters. The reaction proceeds under metal-free conditions by using N-heterocyclic carbenes as organocatalysts in combination with environmentally friendly oxygen as the terminal oxidation agent. PMID:23616801

  8. Diastereoselective synthesis of substituted diaziridines from simple ketones and aldehydes.

    PubMed

    Beebe, Alexander W; Dohmeier, Emma F; Moura-Letts, Gustavo

    2015-09-11

    Diastereopure substituted diaziridines from simple ketones, aldehydes and amines are here reported. These important chemical scaffolds are obtained in the presence of a weak inorganic base and hydroxylamine O-sulfonic acid (HOSA). This method introduces three stereocenters in one step to provide a wide variety of substituted diaziridines with high yields and diastereoselectivities.

  9. 40 CFR 721.5762 - Aromatic aldehyde phenolic resin (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Aromatic aldehyde phenolic resin (generic). 721.5762 Section 721.5762 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.5762...

  10. A thermostable transketolase evolved for aliphatic aldehyde acceptors.

    PubMed

    Yi, Dong; Saravanan, Thangavelu; Devamani, Titu; Charmantray, Franck; Hecquet, Laurence; Fessner, Wolf-Dieter

    2015-01-11

    Directed evolution of the thermostable transketolase from Geobacillus stearothermophilus based on a pH-based colorimetric screening of smart libraries yielded several mutants with up to 16-fold higher activity for aliphatic aldehydes and high enantioselectivity (>95% ee) in the asymmetric carboligation step. PMID:25415647

  11. Antibiotics from basidiomycetes. 26. Phlebiakauranol aldehyde an antifungal and cytotoxic metabolite from Punctularia atropurpurascens.

    PubMed

    Anke, H; Casser, I; Steglich, W; Pommer, E H

    1987-04-01

    Phlebiakauranol aldehyde and the corresponding alcohol were isolated from cultures of Punctularia atropurpurascens. The aldehyde but not the alcohol exhibited strong antifungal activity against several phytopathogens as well as antibacterial and cytotoxic activities. Two acetylated derivatives prepared from the aldehyde showed only very weak antifungal and antibacterial and moderate cytotoxic activities. We therefore assume, that the aldehyde group together with the high number of hydroxyl groups are responsible for the biological activity of the compound.

  12. Activator Protein-1 Regulation of Murine Aldehyde Dehydrogenase 1a1

    PubMed Central

    Makia, N. L.; Amunom, I.; Falkner, K. C.; Conklin, D. J.; Surapureddi, S.; Goldstein, J. A.

    2012-01-01

    Previously we demonstrated that aldehyde dehydrogenase (ALDH) 1a1 is the major ALDH expressed in mouse liver and is an effective catalyst in metabolism of lipid aldehydes. Quantitative real-time polymerase chain reaction analysis revealed a ≈2.5- to 3-fold induction of the hepatic ALDH1A1 mRNA in mice administered either acrolein (5 mg/kg acrolein p.o.) or butylated hydroxylanisole (BHA) (0.45% in the diet) and of cytosolic NAD+-dependent ALDH activity. We observed ≈2-fold increases in ALDH1A1 mRNA levels in both Nrf2(+/+) and Nrf2(−/−) mice treated with BHA compared with controls, suggesting that BHA-induced expression is independent of nuclear factor E2-related factor 2 (Nrf2). The levels of activator protein-1 (AP-1) mRNA and protein, as well as the amount of phosphorylated c-Jun were significantly increased in mouse liver or Hepa1c1c7 cells treated with either BHA or acrolein. With use of luciferase reporters containing the 5′-flanking sequence of Aldh1a1 (−1963/+27), overexpression of c-Jun resulted in an ≈4-fold induction in luciferase activity, suggesting that c-Jun transactivates the Aldh1a1 promoter as a homodimer and not as a c-Jun/c-Fos heterodimer. Promoter deletion and mutagenesis analyses demonstrated that the AP-1 site at position −758 and possibly −1069 relative to the transcription start site was responsible for c-Jun-mediated transactivation. Electrophoretic mobility shift assay analysis with antibodies against c-Jun and c-Fos showed that c-Jun binds to the proximal AP-1 site at position −758 but not at −1069. Recruitment of c-Jun to this proximal AP-1 site by BHA was confirmed by chromatin immunoprecipitation analysis, indicating that recruitment of c-Jun to the mouse Aldh1a1 gene promoter results in increased transcription. This mode of regulation of an ALDH has not been described before. PMID:22740640

  13. Conjugation in "Escherichia coli"

    ERIC Educational Resources Information Center

    Phornphisutthimas, Somkiat; Thamchaipenet, Arinthip; Panijpan, Bhinyo

    2007-01-01

    Bacterial conjugation is a genetic transfer that involves cell-to-cell between donor and recipient cells. With the current method used to teach students in genetic courses at the undergraduate level, the transconjugants are identified using bacterial physiology and/or antibiotic resistance. Using physiology, however, is difficult for both…

  14. DNA-cell conjugates

    DOEpatents

    Hsiao, Shih-Chia; Francis, Matthew B.; Bertozzi, Carolyn; Mathies, Richard; Chandra, Ravi; Douglas, Erik; Twite, Amy; Toriello, Nicholas; Onoe, Hiroaki

    2016-05-03

    The present invention provides conjugates of DNA and cells by linking the DNA to a native functional group on the cell surface. The cells can be without cell walls or can have cell walls. The modified cells can be linked to a substrate surface and used in assay or bioreactors.

  15. Functional Specialization of Maize Mitochondrial Aldehyde Dehydrogenases1

    PubMed Central

    Liu, Feng; Schnable, Patrick S.

    2002-01-01

    The maize (Zea mays) rf2a and rf2b genes both encode homotetrameric aldehyde dehydrogenases (ALDHs). The RF2A protein was shown previously to accumulate in the mitochondria. In vitro import experiments and ALDH assays on mitochondrial extracts from rf2a mutant plants established that the RF2B protein also accumulates in the mitochondria. RNA gel-blot analyses and immunohistolocation experiments revealed that these two proteins have only partially redundant expression patterns in organs and cell types. For example, RF2A, but not RF2B, accumulates to high levels in the tapetal cells of anthers. Kinetic analyses established that RF2A and RF2B have quite different substrate specificities; although RF2A can oxidize a broad range of aldehydes, including aliphatic aldehydes and aromatic aldehydes, RF2B can oxidize only short-chain aliphatic aldehydes. These two enzymes also have different pH optima and responses to changes in substrate concentration. In addition, RF2A, but not RF2B or any other natural ALDHs, exhibits positive cooperativity. These functional specializations may explain why many species have two mitochondrial ALDHs. This study provides data that serve as a basis for identifying the physiological pathway by which the rf2a gene participates in normal anther development and the restoration of Texas cytoplasm-based male sterility. For example, the observations that Texas cytoplasm anthers do not accumulate elevated levels of reactive oxygen species or lipid peroxidation and the kinetic features of RF2A make it unlikely that rf2a restores fertility by preventing premature programmed cell death. PMID:12481049

  16. Derivatization Strategy for the Comprehensive Characterization of Endogenous Fatty Aldehydes Using HPLC-Multiple Reaction Monitoring.

    PubMed

    Tie, Cai; Hu, Ting; Jia, Zhi-Xin; Zhang, Jin-Lan

    2016-08-01

    Fatty aldehydes are crucial substances that mediate a wide range of vital physiological functions, particularly lipid peroxidation. Fatty aldehydes such as acrolein and 4-hydroxynonenal (4-HNE) are considered potential biomarkers of myocardial ischemia and dementia, but analytical techniques for fatty aldehydes are lacking. In the present study, a comprehensive characterization strategy with high sensitivity and facility for fatty aldehydes based on derivatization and high-performance liquid chromatography-multiple reaction monitoring (HPLC-MRM) was developed. The fatty aldehydes of a biosample were derivatized using 2,4-bis(diethylamino)-6-hydrazino-1,3,5-triazine under mild and efficient reaction conditions at 37 °C for 15 min. The limit of detection (LOD) of the fatty aldehydes varied from 0.1 to 1 pg/mL, depending on the structures of these molecules. General MRM parameters were forged for the analysis of endogenous fatty aldehydes. "Heavy" derivatization reagents with 20 deuterium atoms were synthesized for both the discovery and comprehensive characterization of fatty aldehydes. More than 80 fatty aldehydes were detected in the biosamples. The new strategy was successfully implemented in global fatty aldehyde profiling of plasma and brain tissue of the bilateral common carotid artery (2VO) dementia rat model. Dozens of fatty aldehydes were significantly changed between the control and model groups. These findings further highlight the importance of endogenous fatty aldehydes. PMID:27397858

  17. In vitro degradation of hexanitrohexaazaisowurtzitane (CL-20) by cytosolic enzymes of Japanese quail and the rabbit.

    PubMed

    Bardai, Ghalib K; Halasz, Annamaria; Sunahara, Geoffrey I; Dodard, Sabine; Spear, Philip A; Grosse, Stephan; Hoang, Johnston; Hawari, Jalal

    2006-12-01

    Hexanitrohexaazaisowurtzitane (CL-20) is a polycyclic nitramine explosive and propellant, currently being considered as a potential replacement for existing cyclic nitramine explosives. Earlier studies have provided evidence suggestive of adverse liver effects in adult Coturnix spp. exposed to CL-20, yet analysis of tissue samples (plasma, liver, brain, heart, or spleen) indicated that CL-20 was not detectable in these treated animals. The present study was conducted to identify and purify the enzymes capable of CL-20 biotransformation. Results indicate that the hepatic biotransformation of CL-20 in vitro was inhibited by ethacrynic acid (93%) and by the glutathione (GSH) analogue S-octylglutathione (80%), suggesting the involvement of glutathione-S-transferase (GST). Partially purified cytosolic alpha- and mu-type GST (requiring presence of GSH as a cofactor) from quail and rabbit liver was capable of CL-20 biotransformation. The degradation of CL-20 (0.30 +/- 0.05 and 0.40 +/- 0.02 nmol/min/mg protein for quail and rabbit, respectively) was accompanied with the formation of nitrite and consumption of GSH. Using liquid chromatography/mass spectrometry, we detected two intermediates, that is, open-ring, monodenitrated GSH-conjugated CL-20 biotransformation product with the same deprotonated molecular mass ion at 699 Da, suggesting isomeric forms of the intermediate metabolites. Identity of the conjugated metabolites was confirmed by using ring-labeled [15N]CL-20 and the nitro group-labeled [15NO2]CL-20. These data suggest that the in vitro biotransformation of CL-20 by GST under the conditions tested may be a key initial step in the in vivo degradation of CL-20 in the quail and resulted in the formation of more biologically reactive intermediates than the parent compound. These data will aid in our understanding of the biotransformation processes of CL-20 in vivo.

  18. In vitro degradation of hexanitrohexaazaisowurtzitane (CL-20) by cytosolic enzymes of Japanese quail and the rabbit.

    PubMed

    Bardai, Ghalib K; Halasz, Annamaria; Sunahara, Geoffrey I; Dodard, Sabine; Spear, Philip A; Grosse, Stephan; Hoang, Johnston; Hawari, Jalal

    2006-12-01

    Hexanitrohexaazaisowurtzitane (CL-20) is a polycyclic nitramine explosive and propellant, currently being considered as a potential replacement for existing cyclic nitramine explosives. Earlier studies have provided evidence suggestive of adverse liver effects in adult Coturnix spp. exposed to CL-20, yet analysis of tissue samples (plasma, liver, brain, heart, or spleen) indicated that CL-20 was not detectable in these treated animals. The present study was conducted to identify and purify the enzymes capable of CL-20 biotransformation. Results indicate that the hepatic biotransformation of CL-20 in vitro was inhibited by ethacrynic acid (93%) and by the glutathione (GSH) analogue S-octylglutathione (80%), suggesting the involvement of glutathione-S-transferase (GST). Partially purified cytosolic alpha- and mu-type GST (requiring presence of GSH as a cofactor) from quail and rabbit liver was capable of CL-20 biotransformation. The degradation of CL-20 (0.30 +/- 0.05 and 0.40 +/- 0.02 nmol/min/mg protein for quail and rabbit, respectively) was accompanied with the formation of nitrite and consumption of GSH. Using liquid chromatography/mass spectrometry, we detected two intermediates, that is, open-ring, monodenitrated GSH-conjugated CL-20 biotransformation product with the same deprotonated molecular mass ion at 699 Da, suggesting isomeric forms of the intermediate metabolites. Identity of the conjugated metabolites was confirmed by using ring-labeled [15N]CL-20 and the nitro group-labeled [15NO2]CL-20. These data suggest that the in vitro biotransformation of CL-20 by GST under the conditions tested may be a key initial step in the in vivo degradation of CL-20 in the quail and resulted in the formation of more biologically reactive intermediates than the parent compound. These data will aid in our understanding of the biotransformation processes of CL-20 in vivo. PMID:17220092

  19. Aromatic aldehyde-catalyzed gas-phase decarboxylation of amino acid anion via imine intermediate: An experimental and theoretical study

    NASA Astrophysics Data System (ADS)

    Xiang, Zhang

    2013-10-01

    It is generally appreciated that carbonyl compound can promote the decarboxylation of the amino acid. In this paper, we have performed the experimental and theoretical investigation into the gas-phase decarboxylation of the amino acid anion catalyzed by the aromatic aldehyde via the imine intermediate on the basis of the tandem mass spectrometry (MS/MS) technique and density functional theory (DFT) calculation. The results show that the aromatic aldehyde can achieve a remarkable catalytic effect. Moreover, the catalytic mechanism varies according to the type of amino acid: (i) The decarboxylation of α-amino acid anion is determined by the direct dissociation of the Csbnd C bond adjacent to the carboxylate, for the resulting carbanion can be well stabilized by the conjugation between α-carbon, Cdbnd N bond and benzene ring. (ii) The decarboxylation of non-α-amino acid anion proceeds via a SN2-like transition state, in which the dissociation of the Csbnd C bond adjacent to the carboxylate and attacking of the resulting carbanion to the Cdbnd N bond or benzene ring take place at the same time. Specifically, for β-alanine, the resulting carbanion preferentially attacks the benzene ring leading to the benzene anion, because attacking the Cdbnd N bond in the decarboxylation can produce the unstable three or four-membered ring anion. For the other non-α-amino acid anion, the Cdbnd N bond preferentially participates in the decarboxylation, which leads to the pediocratic nitrogen anion.

  20. GRE2 from Scheffersomyces stipitis as an aldehyde reductase contributes tolerance to aldehyde inhibitors derived from lignocellulosic biomass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Scheffersomyces (Pichia) stipitis is one of the most promising yeasts for industrial bioethanol production from lignocellulosic biomass. S. stipitis is able to in situ detoxify aldehyde inhibitors [such as furfural and 5-hydroxymethylfurfural (HMF)] to less toxic corresponding alcohols. However, the...

  1. Targeted systemic mesenchymal stem cell delivery using hyaluronate - wheat germ agglutinin conjugate.

    PubMed

    Kim, Yun Seop; Kong, Won Ho; Kim, Hyemin; Hahn, Sei Kwang

    2016-11-01

    A variety of receptors for hyaluronate (HA), a natural linear polysaccharide, were found in the body, which have been exploited as target sites for HA-based drug delivery systems. In this work, mesenchymal stem cells (MSCs) were surface-modified with HA - wheat germ agglutinin (WGA) conjugate for targeted systemic delivery of MSCs to the liver. WGA was conjugated to HA by coupling reaction between aldehyde-modified HA and amine group of WGA. The conjugation of WGA to HA was corroborated by gel permeation chromatography (GPC) and the successful surface modification of MSCs with HA-WGA conjugate was confirmed by confocal microscopy. The synthesized HA-WGA conjugate could be incorporated onto the cellular membrane by agglutinating the cell-associated carbohydrates. Fluorescent imaging for in vivo biodistribution visualized the targeted delivery of the HA-WGA/MSC complex to the liver after intravenous injection. This new strategy for targeted delivery of MSCs using HA-WGA conjugate might be successfully exploited for various regenerative medicines including cell therapy. PMID:27569867

  2. Aldehyde sources, metabolism, molecular toxicity mechanisms, and possible effects on human health.

    PubMed

    O'Brien, Peter J; Siraki, Arno G; Shangari, Nandita

    2005-08-01

    Aldehydes are organic compounds that are widespread in nature. They can be formed endogenously by lipid peroxidation (LPO), carbohydrate or metabolism ascorbate autoxidation, amine oxidases, cytochrome P-450s, or myeloperoxidase-catalyzed metabolic activation. This review compares the reactivity of many aldehydes towards biomolecules particularly macromolecules. Furthermore, it includes not only aldehydes of environmental or occupational concerns but also dietary aldehydes and aldehydes formed endogenously by intermediary metabolism. Drugs that are aldehydes or form reactive aldehyde metabolites that cause side-effect toxicity are also included. The effects of these aldehydes on biological function, their contribution to human diseases, and the role of nucleic acid and protein carbonylation/oxidation in mutagenicity and cytotoxicity mechanisms, respectively, as well as carbonyl signal transduction and gene expression, are reviewed. Aldehyde metabolic activation and detoxication by metabolizing enzymes are also reviewed, as well as the toxicological and anticancer therapeutic effects of metabolizing enzyme inhibitors. The human health risks from clinical and animal research studies are reviewed, including aldehydes as haptens in allergenic hypersensitivity diseases, respiratory allergies, and idiosyncratic drug toxicity; the potential carcinogenic risks of the carbonyl body burden; and the toxic effects of aldehydes in liver disease, embryo toxicity/teratogenicity, diabetes/hypertension, sclerosing peritonitis, cerebral ischemia/neurodegenerative diseases, and other aging-associated diseases.

  3. Stapled endosome disrupting alginate particles for cytosolic delivery of cations.

    PubMed

    Acharya, Abhinav P; Little, Steven R

    2015-01-01

    Divalent cations, the most prevalent minerals in the body, are responsible for a wide variety of cellular functions including signaling, proliferation, differentiation and cell death, and therefore their transmembrane transportation is tightly regulated. Despite the importance of divalent cations in cell activity, there are currently no intracellular delivery methods for divalent cations or modulation of intracellular levels of minerals. Here, we describe endosome disrupting alginate nanoparticles termed Alginoketals, which can deliver divalent cations to the cytosol of the cells. Alginoketals are generated by crosslinking alginic acid with endosome disrupting ketals, and using divalent cations as the stapling or binding agent. We show that Alginoketals were able to deliver copper (II) in the cytosol of the cancer cells thereby disrupting copper homeostasis and inducing cell death via accumulation of hydrogen peroxide. Alginoketal-copper (II)-based particles act as superoxide dismutase mimics and are the first class of divalent cation delivery vehicles, with potential application in cancer therapy, regenerative medicine and drug delivery.

  4. Conjugated polymer nanoparticles

    NASA Astrophysics Data System (ADS)

    Tuncel, Dönüs; Demir, Hilmi Volkan

    2010-04-01

    Conjugated polymer nanoparticles are highly versatile nano-structured materials that can potentially find applications in various areas such as optoelectronics, photonics, bio-imaging, bio-sensing and nanomedicine. Their straightforward synthesis in desired sizes and properties, biocompatibility and non-toxicity make these materials highly attractive for the aforementioned applications. This feature article reviews the recent developments in the synthesis, characterization, properties and application of these exciting nanostructured materials.

  5. Anti- (conjugate) linearity

    NASA Astrophysics Data System (ADS)

    Uhlmann, Armin

    2016-03-01

    This is an introduction to antilinear operators. In following Wigner the terminus antilinear is used as it is standard in Physics. Mathematicians prefer to say conjugate linear. By restricting to finite-dimensional complex-linear spaces, the exposition becomes elementary in the functional analytic sense. Nevertheless it shows the amazing differences to the linear case. Basics of antilinearity is explained in sects. 2, 3, 4, 7 and in sect. 1.2: Spectrum, canonical Hermitian form, antilinear rank one and two operators, the Hermitian adjoint, classification of antilinear normal operators, (skew) conjugations, involutions, and acq-lines, the antilinear counterparts of 1-parameter operator groups. Applications include the representation of the Lagrangian Grassmannian by conjugations, its covering by acq-lines. As well as results on equivalence relations. After remembering elementary Tomita-Takesaki theory, antilinear maps, associated to a vector of a two-partite quantum system, are defined. By allowing to write modular objects as twisted products of pairs of them, they open some new ways to express EPR and teleportation tasks. The appendix presents a look onto the rich structure of antilinear operator spaces.

  6. Conjugate flow action functionals

    SciTech Connect

    Venturi, Daniele

    2013-11-15

    We present a new general framework to construct an action functional for a non-potential field theory. The key idea relies on representing the governing equations relative to a diffeomorphic flow of curvilinear coordinates which is assumed to be functionally dependent on the solution field. Such flow, which will be called the conjugate flow, evolves in space and time similarly to a physical fluid flow of classical mechanics and it can be selected in order to symmetrize the Gâteaux derivative of the field equations with respect to suitable local bilinear forms. This is equivalent to requiring that the governing equations of the field theory can be derived from a principle of stationary action on a Lie group manifold. By using a general operator framework, we obtain the determining equations of such manifold and the corresponding conjugate flow action functional. In particular, we study scalar and vector field theories governed by second-order nonlinear partial differential equations. The identification of transformation groups leaving the conjugate flow action functional invariant could lead to the discovery of new conservation laws in fluid dynamics and other disciplines.

  7. Signaling in the plant cytosol: cysteine or sulfide?

    PubMed

    Gotor, Cecilia; Laureano-Marín, Ana M; Moreno, Inmaculada; Aroca, Ángeles; García, Irene; Romero, Luis C

    2015-10-01

    Cysteine (Cys) is the first organic compound containing reduced sulfur that is synthesized in the last stage of plant photosynthetic assimilation of sulfate. It is a very important metabolite not only because it is crucial for the structure, function and regulation of proteins but also because it is the precursor molecule of an enormous number of sulfur-containing metabolites essential for plant health and development. The biosynthesis of Cys is accomplished by the sequential reaction of serine acetyltransferase (SAT) and O-acetylserine(thiol)synthase (OASTL). In Arabidopsis thaliana, the analysis of specific mutants of members of the SAT and OASTL families has demonstrated that the cytosol is the compartment where the bulk of Cys synthesis takes place and that the cytosolic OASTL enzyme OAS-A1 is the responsible enzyme. Another member of the OASTL family is DES1, a novel L-cysteine desulfhydrase that catalyzes the desulfuration of Cys to produce sulfide, thus acting in a manner opposite to that of OAS-A1. Detailed studies of the oas-a1 and des1 null mutants have revealed the involvement of the DES1 and OAS-A1 proteins in coordinate regulation of Cys homeostasis and the generation of sulfide in the cytosol for signaling purposes. Thus, the levels of Cys in the cytosol strongly affect plant responses to both abiotic and biotic stress conditions, while sulfide specifically generated from the degradation of Cys negatively regulates autophagy induced in different situations. In conclusion, modulation of the levels of Cys and sulfide is likely critical for plant performance.

  8. Labeling Cytosolic Targets in Live Cells with Blinking Probes

    PubMed Central

    Xu, Jianmin; Chang, Jason; Yan, Qi; Dertinger, Thomas; Bruchez, Marcel; Weiss, Shimon

    2013-01-01

    With the advent of superresolution imaging methods, fast dynamic imaging of biological processes in live cells remains a challenge. A subset of these methods requires the cellular targets to be labeled with spontaneously blinking probes. The delivery and specific targeting of cytosolic targets and the control of the probes’ blinking properties are reviewed for three types of blinking probes: quantum dots, synthetic dyes, and fluorescent proteins. PMID:23930154

  9. Purification and characterization of protein Z from rabbit liver cytosol.

    PubMed

    Vincent, S H; Holeman, B; Muller-Eberhard, U

    1985-10-30

    Protein Z was purified from rabbit liver cytosol by affinity chromatography on oleic acid-agarose and preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. After removal of sodium dodecyl sulfate, the renatured protein was found to bind heme and bilirubin with a Kd of approximately 1 microM which produced large red shifts in their absorption spectra. On isoelectric focusing, rabbit protein Z exhibited two main bands with pI around 6.0.

  10. Inhibition of phospholipid methylation by a cytosolic factor.

    PubMed Central

    Alvarez Chiva, V; Mato, J M

    1984-01-01

    Rat liver cytosol contains a heat-stable factor which inhibits phospholipid methylation by rat liver microsomes. The effect of this factor on lipid methylation was dose- and pH-dependent. This factor has an Mr of approx. 3200 as estimated by gel filtration. It could not be extracted by chloroform/methanol (2:1, v/v), and its action was inhibited by incubation with subtilisin. PMID:6712636

  11. Light induced cytosolic drug delivery from liposomes with gold nanoparticles.

    PubMed

    Lajunen, Tatu; Viitala, Lauri; Kontturi, Leena-Stiina; Laaksonen, Timo; Liang, Huamin; Vuorimaa-Laukkanen, Elina; Viitala, Tapani; Le Guével, Xavier; Yliperttula, Marjo; Murtomäki, Lasse; Urtti, Arto

    2015-04-10

    Externally triggered drug release at defined targets allows site- and time-controlled drug treatment regimens. We have developed liposomal drug carriers with encapsulated gold nanoparticles for triggered drug release. Light energy is converted to heat in the gold nanoparticles and released to the lipid bilayers. Localized temperature increase renders liposomal bilayers to be leaky and triggers drug release. The aim of this study was to develop a drug releasing system capable of releasing its cargo to cell cytosol upon triggering with visible and near infrared light signals. The liposomes were formulated using either heat-sensitive or heat- and pH-sensitive lipid compositions with star or rod shaped gold nanoparticles. Encapsulated fluorescent probe, calcein, was released from the liposomes after exposure to the light. In addition, the pH-sensitive formulations showed a faster drug release in acidic conditions than in neutral conditions. The liposomes were internalized into human retinal pigment epithelial cells (ARPE-19) and human umbilical vein endothelial cells (HUVECs) and did not show any cellular toxicity. The light induced cytosolic delivery of calcein from the gold nanoparticle containing liposomes was shown, whereas no cytosolic release was seen without light induction or without gold nanoparticles in the liposomes. The light activated liposome formulations showed a controlled content release to the cellular cytosol at a specific location and time. Triggering with visual and near infrared light allows good tissue penetration and safety, and the pH-sensitive liposomes may enable selective drug release in the intracellular acidic compartments (endosomes, lysosomes). Thus, light activated liposomes with gold nanoparticles are an attractive option for time- and site-specific drug delivery into the target cells.

  12. Signaling in the plant cytosol: cysteine or sulfide?

    PubMed

    Gotor, Cecilia; Laureano-Marín, Ana M; Moreno, Inmaculada; Aroca, Ángeles; García, Irene; Romero, Luis C

    2015-10-01

    Cysteine (Cys) is the first organic compound containing reduced sulfur that is synthesized in the last stage of plant photosynthetic assimilation of sulfate. It is a very important metabolite not only because it is crucial for the structure, function and regulation of proteins but also because it is the precursor molecule of an enormous number of sulfur-containing metabolites essential for plant health and development. The biosynthesis of Cys is accomplished by the sequential reaction of serine acetyltransferase (SAT) and O-acetylserine(thiol)synthase (OASTL). In Arabidopsis thaliana, the analysis of specific mutants of members of the SAT and OASTL families has demonstrated that the cytosol is the compartment where the bulk of Cys synthesis takes place and that the cytosolic OASTL enzyme OAS-A1 is the responsible enzyme. Another member of the OASTL family is DES1, a novel L-cysteine desulfhydrase that catalyzes the desulfuration of Cys to produce sulfide, thus acting in a manner opposite to that of OAS-A1. Detailed studies of the oas-a1 and des1 null mutants have revealed the involvement of the DES1 and OAS-A1 proteins in coordinate regulation of Cys homeostasis and the generation of sulfide in the cytosol for signaling purposes. Thus, the levels of Cys in the cytosol strongly affect plant responses to both abiotic and biotic stress conditions, while sulfide specifically generated from the degradation of Cys negatively regulates autophagy induced in different situations. In conclusion, modulation of the levels of Cys and sulfide is likely critical for plant performance. PMID:24990521

  13. Cytosolic Replication of Group A Streptococcus in Human Macrophages

    PubMed Central

    O’Neill, Alan M.; Thurston, Teresa L. M.

    2016-01-01

    ABSTRACT As key components of innate immune defense, macrophages are essential in controlling bacterial pathogens, including group A Streptococcus (GAS). Despite this, only a limited number of studies have analyzed the recovery of GAS from within human neutrophils and macrophages. Here, we determined the intracellular fate of GAS in human macrophages by using several quantitative approaches. In both U937 and primary human macrophages, the appearance over time of long GAS chains revealed that despite GAS-mediated cytotoxicity, replication occurred in viable, propidium iodide-negative macrophages. Whereas the major virulence factor M1 did not contribute to bacterial growth, a GAS mutant strain deficient in streptolysin O (SLO) was impaired for intracellular replication. SLO promoted bacterial escape from the GAS-containing vacuole (GCV) into the macrophage cytosol. Up to half of the cytosolic GAS colocalized with ubiquitin and p62, suggesting that the bacteria were targeted by the autophagy machinery. Despite this, live imaging of U937 macrophages revealed proficient replication of GAS after GCV rupture, indicating that escape from the GCV is important for growth of GAS in macrophages. Our results reveal that GAS can replicate within viable human macrophages, with SLO promoting GCV escape and cytosolic growth, despite the recruitment of autophagy receptors to bacteria. PMID:27073088

  14. Cytosolic Calcium Measurements in Renal Epithelial Cells by Flow Cytometry

    PubMed Central

    Lee, Wing-Kee; Dittmar, Thomas

    2014-01-01

    A variety of cellular processes, both physiological and pathophysiological, require or are governed by calcium, including exocytosis, mitochondrial function, cell death, cell metabolism and cell migration to name but a few. Cytosolic calcium is normally maintained at low nanomolar concentrations; rather it is found in high micromolar to millimolar concentrations in the endoplasmic reticulum, mitochondrial matrix and the extracellular compartment. Upon stimulation, a transient increase in cytosolic calcium serves to signal downstream events. Detecting changes in cytosolic calcium is normally performed using a live cell imaging set up with calcium binding dyes that exhibit either an increase in fluorescence intensity or a shift in the emission wavelength upon calcium binding. However, a live cell imaging set up is not freely accessible to all researchers. Alternative detection methods have been optimized for immunological cells with flow cytometry and for non-immunological adherent cells with a fluorescence microplate reader. Here, we describe an optimized, simple method for detecting changes in epithelial cells with flow cytometry using a single wavelength calcium binding dye. Adherent renal proximal tubule epithelial cells, which are normally difficult to load with dyes, were loaded with a fluorescent cell permeable calcium binding dye in the presence of probenecid, brought into suspension and calcium signals were monitored before and after addition of thapsigargin, tunicamycin and ionomycin. PMID:25407650

  15. A reaction-diffusion model of cytosolic hydrogen peroxide.

    PubMed

    Lim, Joseph B; Langford, Troy F; Huang, Beijing K; Deen, William M; Sikes, Hadley D

    2016-01-01

    As a signaling molecule in mammalian cells, hydrogen peroxide (H2O2) determines the thiol/disulfide oxidation state of several key proteins in the cytosol. Localization is a key concept in redox signaling; the concentrations of signaling molecules within the cell are expected to vary in time and in space in manner that is essential for function. However, as a simplification, all theoretical studies of intracellular hydrogen peroxide and many experimental studies to date have treated the cytosol as a well-mixed compartment. In this work, we incorporate our previously reported reduced kinetic model of the network of reactions that metabolize hydrogen peroxide in the cytosol into a model that explicitly treats diffusion along with reaction. We modeled a bolus addition experiment, solved the model analytically, and used the resulting equations to quantify the spatiotemporal variations in intracellular H2O2 that result from this kind of perturbation to the extracellular H2O2 concentration. We predict that micromolar bolus additions of H2O2 to suspensions of HeLa cells (0.8 × 10(9)cells/l) result in increases in the intracellular concentration that are localized near the membrane. These findings challenge the assumption that intracellular concentrations of H2O2 are increased uniformly throughout the cell during bolus addition experiments and provide a theoretical basis for differing phenotypic responses of cells to intracellular versus extracellular perturbations to H2O2 levels.

  16. Regulation of cytosolic free calcium concentration by intrasynaptic mitochondria.

    PubMed Central

    Martínez-Serrano, A; Satrústegui, J

    1992-01-01

    By the use of digitonin permeabilized presynaptic nerve terminals (synaptosomes), we have found that intrasynaptic mitochondria, when studied "in situ," i.e., surrounded by their cytosolic environment, are able to buffer calcium in a range of calcium concentrations close to those usually present in the cytosol of resting synaptosomes. Adenine nucleotides and polyamines, which are usually lost during isolation of mitochondria, greatly improve the calcium-sequestering activity of mitochondria in permeabilized synaptosomes. The hypothesis that the mitochondria contributes to calcium homeostasis at low resting cytosolic free calcium concentration ([Ca2+]i) in synaptosomes has been tested; it has been found that in fact this is the case. Intrasynaptic mitochondria actively accumulates calcium at [Ca2+]i around 10(-7) M, and this activity is necessary for the regulation of [Ca2+]i. When compared with other membrane-limited calcium pools, it was found that depending on external concentration the calcium pool mobilized from mitochondria is similar or even greater than the IP3- or caffeine-sensitive calcium pools. In summary, the results presented argue in favor of a more prominent role of mitochondria in regulating [Ca2+]i in presynaptic nerve terminals, a role that should be reconsidered for other cellular types in light of the present evidence. PMID:1550964

  17. Wind-induced plant motion immediately increases cytosolic calcium.

    PubMed Central

    Knight, M R; Smith, S M; Trewavas, A J

    1992-01-01

    Wind is one of the most unusual and more dramatic of the environmental signals to modify plant development. Wind-stimulated crops are also known to experience considerable reductions in growth and subsequent yield. There is at present no experimental data to suggest how wind signals are perceived and transduced by plant cells. We have genetically transformed Nicotiana plumbaginifolia to express aequorin and thus produced luminous plants that directly report cytosolic calcium by emitting blue light. With these plants we have found wind stimulation to cause immediate increases in cytosolic calcium and our evidence, based on the use of specific inhibitors, suggests that this calcium is mobilized from organelle sources. Our data further suggest that wind-induced movement of tissues, by mechanically stimulating and stressing constituent plant cells, is responsible for the immediate elevation of cytosolic calcium; increases occur only when the plant tissue is actually in motion. Repeated wind stimulation renders the cells refractory to further calcium signaling but responsiveness is rapidly recovered when stimulation is subsequently diminished. Our data suggest that mechanoperception in plant cells may possibly be transduced through intracellular calcium. Since mechanoperception and transduction are considered crucial to plant morphogenesis, our observations suggest that calcium could be central in the control and generation of plant form. Images PMID:11536497

  18. Diacylglycerol kinase activity in brain cytosol and microsomes

    SciTech Connect

    Kelleher, J.A.; Sun, G.Y.

    1986-05-01

    The ATP-dependent diacylglycerol (DG) kinase phosphorylated DG to form phosphatidic acids (PA). This enzymic conversion is particularly important in the receptor-mediated polyphosphoinositide metabolism. Controlling the DG level in synaptic membranes can also modulate the protein kinase activity within the cell. Using /sup 32/P-ATP, MgCl/sub 2/, NaF and heat treated membranes as substrate, DG-kinase activity was found in both cytosolic and microsomal fractions. Similarities in properties between the two kinase activities were noted. For example, activities in both fractions were stimulated by deoxycholate, and were inhibited by dibucaine and propranol. These results suggest that the microsomal and cytosolic DG-kinase(s) may belong to the same enzyme and that some intracellular factors may be responsible for regulation of the enzyme for interaction with membrane substrate. One of the factors tested was free fatty acid (FFA) which appeared to promote translocation of the cytosolic enzyme to the microsomes. Another factor for regulation is the availability of DG, which is formed via the poly-PI phosphodiesterase in synaptosomes and PA-phosphohydrolase in the microsomes (for de novo biosynthesis of phospholipids). Possible physiological significance of these regulatory mechanisms will be addressed.

  19. Role of Cytosolic Calcium Diffusion in Murine Cardiac Purkinje Cells

    PubMed Central

    Limbu, Bijay; Shah, Kushal; Weinberg, Seth H.; Deo, Makarand

    2016-01-01

    Cardiac Purkinje cells (PCs) are morphologically and electrophysiologically different from ventricular myocytes and, importantly, exhibit distinct calcium (Ca2+) homeostasis. Recent studies suggest that PCs are more susceptible to action potential (AP) abnormalities than ventricular myocytes; however, the exact mechanisms are poorly understood. In this study, we utilized a detailed biophysical mathematical model of a murine PC to systematically examine the role of cytosolic Ca2+ diffusion in shaping the AP in PCs. A biphasic spatiotemporal Ca2+ diffusion process, as recorded experimentally, was implemented in the model. In this study, we investigated the role of cytosolic Ca2+ dynamics on AP and ionic current properties by varying the effective Ca2+ diffusion rate. It was observed that AP morphology, specifically the plateau, was affected due to changes in the intracellular Ca2+ dynamics. Elevated Ca2+ concentration in the sarcolemmal region activated inward sodium–Ca2+ exchanger (NCX) current, resulting in a prolongation of the AP plateau at faster diffusion rates. Artificially clamping the NCX current to control values completely reversed the alterations in the AP plateau, thus confirming the role of NCX in modifying the AP morphology. Our results demonstrate that cytosolic Ca2+ diffusion waves play a significant role in shaping APs of PCs and could provide mechanistic insights in the increased arrhythmogeneity of PCs. PMID:27478391

  20. Inhibition of carbonic anhydrase isoforms I, II, IX and XII with novel Schiff bases: identification of selective inhibitors for the tumor-associated isoforms over the cytosolic ones.

    PubMed

    Sarikaya, Busra; Ceruso, Mariangela; Carta, Fabrizio; Supuran, Claudiu T

    2014-11-01

    A series of new Schiff bases was obtained from sulfanilamide, 3-fluorosulfanilamide or 4-(2-aminoethyl)-benzenesulfonamide and aromatic/heterocyclic aldehydes incorporating both hydrophobic and hydrophilic moieties. The obtained sulfonamides were investigated as inhibitors of four physiologically relevant carbonic anhydrase (CA, EC 4.2.1.1) isoforms, the cytosolic CA I and II, as well as the transmembrane, tumor-associated CA IX and XII. Most derivatives were medium potency or weak hCA I/II inhibitors, but several of them showed nanomolar affinity for CA IX and/or XII, making them an interesting example of isoform-selective compounds. The nature of the aryl/hetaryl moiety present in the initial aldehyde was the main factor influencing potency and isoform selectivity. The best and most CA IX-selective compounds incorporated moieties such as 4-methylthiophenyl, 4-cyanophenyl-, 4-(2-pyridyl)-phenyl and the 4-aminoethylbenzenesulfonamide scaffold. The best hCA XII inhibitors, also showing selectivity for this isoform, incorporated 2-methoxy-4-nitrophenyl-, 2,3,5,6-tetrafluorophenyl and 4-(2-pyridyl)-phenyl functionalities and were also derivatives of 4-aminoethylbenzenesulfonamide. The sulfanilamide and 3-fluorosulfanilamide derived Schiff bases were less active compared to the corresponding 4-aminoethyl-benzenesulfonamide derivatives. As hCA IX/XII selective inhibition is attractive for obtaining antitumor agents/diagnostic tools with a new mechanism of action, compounds of the type described here may be considered interesting preclinical candidates. PMID:25267005

  1. Nucleophilic Iododifluoromethylation of Aldehydes Using Bromine/Iodine Exchange.

    PubMed

    Levin, Vitalij V; Smirnov, Vladimir O; Struchkova, Marina I; Dilman, Alexander D

    2015-09-18

    A method for the iododifluoromethylation of aromatic aldehydes using (bromodifluoromethyl)trimethylsilane (Me3SiCF2Br) is described. The selective formation of the CF2I group is based on using sodium iodide, with the sodium serving as a scavenger of bromide and iodide serving as a nucleophile with respect to difluorocarbene. The primary CF2I-addition products can undergo HI-elimination or iodine/zinc exchange followed by allylation in a one-pot manner.

  2. Aldehyde Dehydrogenases in Cellular Responses to Oxidative/electrophilic Stress

    PubMed Central

    Singh, Surendra; Brocker, Chad; Koppaka, Vindhya; Ying, Chen; Jackson, Brian; Matsumoto, Akiko; Thompson, David C.; Vasiliou, Vasilis

    2013-01-01

    Reactive oxygen species (ROS) are continuously generated within living systems and the inability to manage ROS load leads to elevated oxidative stress and cell damage. Oxidative stress is coupled to the oxidative degradation of lipid membranes, also known as lipid peroxidation. This process generates over 200 types of aldehydes, many of which are highly reactive and toxic. Aldehyde dehydrogenases (ALDHs) metabolize endogenous and exogenous aldehydes and thereby mitigate oxidative/electrophilic stress in prokaryotic and eukaryotic organisms. ALDHs are found throughout the evolutionary gamut, from single celled organisms to complex multicellular species. Not surprisingly, many ALDHs in evolutionarily distant, and seemingly unrelated, species perform similar functions, including protection against a variety of environmental stressors like dehydration and ultraviolet radiation. The ability to act as an ‘aldehyde scavenger’ during lipid peroxidation is another ostensibly universal ALDH function found across species. Up-regulation of ALDHs is a stress response in bacteria (environmental and chemical stress), plants (dehydration, salinity and oxidative stress), yeast (ethanol exposure and oxidative stress), Caenorhabditis elegans (lipid peroxidation) and mammals (oxidative stress and lipid peroxidation). Recent studies have also identified ALDH activity as an important feature of cancer stem cells. In these cells, ALDH expression helps abrogate oxidative stress and imparts resistance against chemotherapeutic agents such as oxazaphosphorine, taxane and platinum drugs. The ALDH superfamily represents a fundamentally important class of enzymes that significantly contributes to the management of electrophilic/oxidative stress within living systems. Mutations in various ALDHs are associated with a variety of pathological conditions in humans, underscoring the fundamental importance of these enzymes in physiological and pathological processes. PMID:23195683

  3. Aldehyde dehydrogenases in cellular responses to oxidative/electrophilic stress.

    PubMed

    Singh, Surendra; Brocker, Chad; Koppaka, Vindhya; Chen, Ying; Jackson, Brian C; Matsumoto, Akiko; Thompson, David C; Vasiliou, Vasilis

    2013-03-01

    Reactive oxygen species (ROS) are continuously generated within living systems and the inability to manage ROS load leads to elevated oxidative stress and cell damage. Oxidative stress is coupled to the oxidative degradation of lipid membranes, also known as lipid peroxidation. This process generates over 200 types of aldehydes, many of which are highly reactive and toxic. Aldehyde dehydrogenases (ALDHs) metabolize endogenous and exogenous aldehydes and thereby mitigate oxidative/electrophilic stress in prokaryotic and eukaryotic organisms. ALDHs are found throughout the evolutionary gamut, from single-celled organisms to complex multicellular species. Not surprisingly, many ALDHs in evolutionarily distant, and seemingly unrelated, species perform similar functions, including protection against a variety of environmental stressors such as dehydration and ultraviolet radiation. The ability to act as an "aldehyde scavenger" during lipid peroxidation is another ostensibly universal ALDH function found across species. Upregulation of ALDHs is a stress response in bacteria (environmental and chemical stress), plants (dehydration, salinity, and oxidative stress), yeast (ethanol exposure and oxidative stress), Caenorhabditis elegans (lipid peroxidation), and mammals (oxidative stress and lipid peroxidation). Recent studies have also identified ALDH activity as an important feature of cancer stem cells. In these cells, ALDH expression helps abrogate oxidative stress and imparts resistance against chemotherapeutic agents such as oxazaphosphorine, taxane, and platinum drugs. The ALDH superfamily represents a fundamentally important class of enzymes that contributes significantly to the management of electrophilic/oxidative stress within living systems. Mutations in various ALDHs are associated with a variety of pathological conditions in humans, highlighting the fundamental importance of these enzymes in physiological and pathological processes. PMID:23195683

  4. Phenazinium salt-catalyzed aerobic oxidative amidation of aromatic aldehydes.

    PubMed

    Leow, Dasheng

    2014-11-01

    Amides are prevalent in organic synthesis. Developing an efficient synthesis that avoids expensive oxidants and heating is highly desirable. Here the oxidative amidation of aromatic aldehydes is reported using an inexpensive metal-free visible light photocatalyst, phenazine ethosulfate, at low catalytic loading (1-2 mol %). The reaction proceeds at ambient temperature and uses air as the sole oxidant. The operationally easy procedure provides an economical, green, and mild alternative for the formation of amide bonds.

  5. Aldehyde dehydrogenases in cellular responses to oxidative/electrophilic stress.

    PubMed

    Singh, Surendra; Brocker, Chad; Koppaka, Vindhya; Chen, Ying; Jackson, Brian C; Matsumoto, Akiko; Thompson, David C; Vasiliou, Vasilis

    2013-03-01

    Reactive oxygen species (ROS) are continuously generated within living systems and the inability to manage ROS load leads to elevated oxidative stress and cell damage. Oxidative stress is coupled to the oxidative degradation of lipid membranes, also known as lipid peroxidation. This process generates over 200 types of aldehydes, many of which are highly reactive and toxic. Aldehyde dehydrogenases (ALDHs) metabolize endogenous and exogenous aldehydes and thereby mitigate oxidative/electrophilic stress in prokaryotic and eukaryotic organisms. ALDHs are found throughout the evolutionary gamut, from single-celled organisms to complex multicellular species. Not surprisingly, many ALDHs in evolutionarily distant, and seemingly unrelated, species perform similar functions, including protection against a variety of environmental stressors such as dehydration and ultraviolet radiation. The ability to act as an "aldehyde scavenger" during lipid peroxidation is another ostensibly universal ALDH function found across species. Upregulation of ALDHs is a stress response in bacteria (environmental and chemical stress), plants (dehydration, salinity, and oxidative stress), yeast (ethanol exposure and oxidative stress), Caenorhabditis elegans (lipid peroxidation), and mammals (oxidative stress and lipid peroxidation). Recent studies have also identified ALDH activity as an important feature of cancer stem cells. In these cells, ALDH expression helps abrogate oxidative stress and imparts resistance against chemotherapeutic agents such as oxazaphosphorine, taxane, and platinum drugs. The ALDH superfamily represents a fundamentally important class of enzymes that contributes significantly to the management of electrophilic/oxidative stress within living systems. Mutations in various ALDHs are associated with a variety of pathological conditions in humans, highlighting the fundamental importance of these enzymes in physiological and pathological processes.

  6. Enantioselective α-Benzylation of Aldehydes via Photoredox Organocatalysis

    PubMed Central

    Shih, Hui-Wen; Vander Wal, Mark N.; Grange, Rebecca L.; MacMillan, David W. C.

    2011-01-01

    The first enantioselective aldehyde α-benzylation using electron-deficient aryl and heteroaryl substrates has been accomplished. The productive merger of a chiral imidazolidinone organocatalyst and a commercially available iridium photoredox catalyst in the presence of household fluorescent light directly affords the desired homobenzylic stereogenicity in good to excellent yield and enantioselectivity. The utility of this methodology has been demonstrated via rapid access to an enantioen-riched drug target for angiogenesis suppression. PMID:20831195

  7. Quantification of the electrophilic reactivities of aldehydes, imines, and enones.

    PubMed

    Appel, Roland; Mayr, Herbert

    2011-06-01

    The rates of the epoxidation reactions of aldehydes, of the aziridination reactions of aldimines, and of the cyclopropanation reactions of α,β-unsaturated ketones with aryl-stabilized dimethylsulfonium ylides have been determined photometrically in dimethyl sulfoxide (DMSO). All of these sulfur ylide-mediated cyclization reactions as well as the addition reactions of stabilized carbanions to N-tosyl-activated aldimines have been shown to follow a second-order rate law, where the rate constants reflect the (initial) CC bond formation between nucleophile and electrophile. The derived second-order rate constants (log k(2)) have been combined with the known nucleophilicity parameters (N, s(N)) of the aryl-stabilized sulfur ylides 4a,b and of the acceptor-substituted carbanions 4c-h to calculate the electrophilicity parameters E of aromatic and aliphatic aldehydes (1a-i), N-acceptor-substituted aromatic aldimines (2a-e), and α,β-unsaturated ketones (3a-f) according to the linear free-energy relationship log k(2) = s(N)(N + E) as defined in J. Am. Chem. Soc.2001, 123, 9500-9512. The data reported in this work provide the first quantitative comparison of the electrophilic reactivities of aldehydes, imines, and simple Michael acceptors in DMSO with carbocations and cationic metal-π complexes within our comprehensive electrophilicity scale. PMID:21553901

  8. γ-Unsaturated aldehydes as potential Lilial replacers.

    PubMed

    Schroeder, Martin; Mathys, Marion; Ehrensperger, Nadja; Büchel, Michelle

    2014-10-01

    A series of Claisen rearrangements was undertaken in order to find a replacement for Lilial (=3-(4-(tert-butyl)phenyl)-2-methylpropanal), a high-tonnage perfumery ingredient with a lily-of-the-valley odour, which is a CMR2 material [1]. 5,7,7-Trimethyl-4-methyleneoctanal (10), the synthesis of which is described, became the main lead. It possesses an odour which is very close to that of Lilial but lacks its substantivity. Aldehydes with higher molecular weights than that of 10 were, therefore, synthesised in order to boost substantivity and to understand the structural requirements for a 'Lilial' odour. The aldehydes were obtained via Claisen rearrangements of 'exo-methylidene' vinyl ethers, allenyl vinyl ethers, or allenyl allyl ethers. Alternatively, coupling of terminal alkynes with allyl alcohols led to the desired aldehydes. Derivatives of 10 and their sila analogues were also synthesised. The olfactory properties of all synthesised molecules were evaluated for possible structure-odour relationships (SOR).

  9. Volatile aldehydes in the mainstream smoke of the narghile waterpipe.

    PubMed

    Al Rashidi, M; Shihadeh, A; Saliba, N A

    2008-11-01

    Very little is known about the quality and quantity of toxicants yielded by the narghile, a subject of increasing importance as this method of tobacco smoking has become popular all over the world. This study is concerned with the identification and quantification of volatile aldehydes in the gas and particle phases of mainstream narghile smoke generated using a popular type of flavored ma'ssel tobacco mixture. These compounds were analyzed based on a modified version of the Environmental Protection Agency compendium method TO-11A. Using a standardized smoking machine protocol consisting of 171 puffs, 2.6s puff duration and 17s inter puff interval, the average yields of formaldehyde, acetaldehyde, acrolein, propionaldehyde and methacrolein were 630, 2520, 892, 403, and 106 microg/smoking session, respectively. The results showed that none of the aldehydes identified in this study are found in the particulate phase of the smoke, except for formaldehyde for which the partitioning coefficient was estimated as Kp = 3.3 x 10(-8) microg/m3. Given previously reported lung absorption fractions of circa 90% for volatile aldehydes, the yields measured in this study are sufficient to induce various diseases depending on the extent of exposure, and on the breathing patterns of the smokers. PMID:18834915

  10. Henry's law constants of some environmentally important aldehydes

    SciTech Connect

    Betterton, E.A.; Hoffmann, M.R.

    1988-12-01

    The Henry's law constants of seven aldehydes have been determined as a function of temperature by bubble-column and by head-space techniques. The compounds were chosen for their potential importance in the polluted troposphere and to allow structure-reactivity patterns to be investigated. The results (at 25/degree/C) are as follows (in units of M atm/sup /minus/1/): chloral, 3.44 /times/ 10/sup 5/; glyoxal, greater than or equal to3 /times/ 10/sup 5/; methylglyoxal, 3.71 /times/ 10/sup 3/; formaldehyde, 2.97 /times/ 10/sup 3/; benzaldehyde, 3.74 /times/ 10/sup 1/; hydroxyacetaldehyde, 4.14 /times/ 10/sup 4/; acetaldehyde, 1.14 /times/ 10/sup 1/. A plot of Taft's parameter, ..sigma..sigma*, vs log H* (the apparent Henry's law constant) gives a straight line with a slope of 1.72. H* for formaldehyde is anomalously high, as expected, but the extremely high value for hydroxyacetaldehyde was unexpected and may indicate that ..cap alpha..-hydroxy-substituted aldehydes could have an usually high affinity for the aqueous phase. The intrinsic Henry's law constants, H, corrected for hydration, do not show a clear structure-reactivity pattern for this series of aldehydes.

  11. Linker-free conjugation and specific cell targeting of antibody functionalized iron-oxide nanoparticles

    PubMed Central

    Xu, Yaolin; Baiu, Dana C.; Sherwood, Jennifer A.; McElreath, Meghan R.; Qin, Ying; Lackey, Kimberly H.; Otto, Mario; Bao, Yuping

    2015-01-01

    Specific targeting is a key step to realize the full potential of iron oxide nanoparticles in biomedical applications, especially tumor-associated diagnosis and therapy. Here, we developed anti-GD2 antibody conjugated iron oxide nanoparticles for highly efficient neuroblastoma cell targeting. The antibody conjugation was achieved through an easy, linker-free method based on catechol reactions. The targeting efficiency and specificity of the antibody-conjugated nanoparticles to GD2-positive neuroblastoma cells were confirmed by flow cytometry, fluorescence microscopy, Prussian blue staining and transmission electron microscopy. These detailed studies indicated that the receptor-recognition capability of the antibody was fully retained after conjugation and the conjugated nanoparticles quickly attached to GD2-positive cells within four hours. Interestingly, longer treatment (12 h) led the cell membrane-bound nanoparticles to be internalized into cytosol, either by directly penetrating the cell membrane or escaping from the endosomes. Last but importantly, the uniquely designed functional surfaces of the nanoparticles allow easy conjugation of other bioactive molecules. PMID:26660881

  12. Ganglioside conjugate vaccines. Immunotherapy against tumors of neuroectodermal origin.

    PubMed

    Helling, F; Livingston, P O

    1994-01-01

    Gangliosides are known to be suitable targets for immune attack against cancer but they are poorly immunogenic. Active immunization with ganglioside/BCG or liposome vaccines results in moderate titer IgM antibody responses of short duration. Covalent attachment of poorly immunogenic antigens to immunogenic proteins is a potent method for inducing an IgG antibody response. GD3, a dominant ganglioside on malignant melanoma, was modified by ozone cleavage of the double bond in the ceramide backbone, an aldehyde group introduced and used for coupling via reductive amination to epsilon-amino-lysyl groups of proteins. Utilizing this method, GD3 conjugates were constructed with: 1. Synthetic multiple antigenic peptide (MAP) constructs expressing 4 repeats of a malaria T-cell epitope; 2. Outer membrane proteins (OMP) of Neisseria meningitidis; 3. Cationized bovine serum albumin; 4. Keyhole limpet hemocyanin (KLH); and 5. Polylysine. In addition, conjugates containing only the GD3 oligosaccharide were synthesized. All constructs were tested for antigenicity using anti-GD3 antibody R24, and for immunogenicity in mice. Serum antibody levels were analyzed by ELISA and immune thin-layer chromatography. Results in the mouse show a significant improvement in the IgM antibody response and a consistent IgG response against GD3 using GD3-KLH conjugates. Other carrier proteins and the use of GD3 oligosaccharide were significantly less effective. If improved immunogenicity and clinical benefit with conjugate vaccines can be demonstrated in patients with melanoma, this approach may be applicable to patients with other tumors of neuroectodermal origin, including gliomas, glioblastomas, astrocytomas, and neuroblastomas.

  13. A Catalase-related Hemoprotein in Coral Is Specialized for Synthesis of Short-chain Aldehydes: DISCOVERY OF P450-TYPE HYDROPEROXIDE LYASE ACTIVITY IN A CATALASE.

    PubMed

    Teder, Tarvi; Lõhelaid, Helike; Boeglin, William E; Calcutt, Wade M; Brash, Alan R; Samel, Nigulas

    2015-08-01

    In corals a catalase-lipoxygenase fusion protein transforms arachidonic acid to the allene oxide 8R,9-epoxy-5,9,11,14-eicosatetraenoic acid from which arise cyclopentenones such as the prostanoid-related clavulones. Recently we cloned two catalase-lipoxygenase fusion protein genes (a and b) from the coral Capnella imbricata, form a being an allene oxide synthase and form b giving uncharacterized polar products (Lõhelaid, H., Teder, T., Tõldsepp, K., Ekins, M., and Samel, N. (2014) PloS ONE 9, e89215). Here, using HPLC-UV, LC-MS, and NMR methods, we identify a novel activity of fusion protein b, establishing its role in cleaving the lipoxygenase product 8R-hydroperoxy-eicosatetraenoic acid into the short-chain aldehydes (5Z)-8-oxo-octenoic acid and (3Z,6Z)-dodecadienal; these primary products readily isomerize in an aqueous medium to the corresponding 6E- and 2E,6Z derivatives. This type of enzymatic cleavage, splitting the carbon chain within the conjugated diene of the hydroperoxide substrate, is known only in plant cytochrome P450 hydroperoxide lyases. In mechanistic studies using (18)O-labeled substrate and incubations in H2(18)O, we established synthesis of the C8-oxo acid and C12 aldehyde with the retention of the hydroperoxy oxygens, consistent with synthesis of a short-lived hemiacetal intermediate that breaks down spontaneously into the two aldehydes. Taken together with our initial studies indicating differing gene regulation of the allene oxide synthase and the newly identified catalase-related hydroperoxide lyase and given the role of aldehydes in plant defense, this work uncovers a potential pathway in coral stress signaling and a novel enzymatic activity in the animal kingdom.

  14. Structural and Kinetic Properties of the Aldehyde Dehydrogenase NahF, a Broad Substrate Specificity Enzyme for Aldehyde Oxidation.

    PubMed

    Coitinho, Juliana B; Pereira, Mozart S; Costa, Débora M A; Guimarães, Samuel L; Araújo, Simara S; Hengge, Alvan C; Brandão, Tiago A S; Nagem, Ronaldo A P

    2016-09-27

    The salicylaldehyde dehydrogenase (NahF) catalyzes the oxidation of salicylaldehyde to salicylate using NAD(+) as a cofactor, the last reaction of the upper degradation pathway of naphthalene in Pseudomonas putida G7. The naphthalene is an abundant and toxic compound in oil and has been used as a model for bioremediation studies. The steady-state kinetic parameters for oxidation of aliphatic or aromatic aldehydes catalyzed by 6xHis-NahF are presented. The 6xHis-NahF catalyzes the oxidation of aromatic aldehydes with large kcat/Km values close to 10(6) M(-1) s(-1). The active site of NahF is highly hydrophobic, and the enzyme shows higher specificity for less polar substrates than for polar substrates, e.g., acetaldehyde. The enzyme shows α/β folding with three well-defined domains: the oligomerization domain, which is responsible for the interlacement between the two monomers; the Rossmann-like fold domain, essential for nucleotide binding; and the catalytic domain. A salicylaldehyde molecule was observed in a deep pocket in the crystal structure of NahF where the catalytic C284 and E250 are present. Moreover, the residues G150, R157, W96, F99, F274, F279, and Y446 were thought to be important for catalysis and specificity for aromatic aldehydes. Understanding the molecular features responsible for NahF activity allows for comparisons with other aldehyde dehydrogenases and, together with structural information, provides the information needed for future mutational studies aimed to enhance its stability and specificity and further its use in biotechnological processes. PMID:27580341

  15. Structural and Kinetic Properties of the Aldehyde Dehydrogenase NahF, a Broad Substrate Specificity Enzyme for Aldehyde Oxidation.

    PubMed

    Coitinho, Juliana B; Pereira, Mozart S; Costa, Débora M A; Guimarães, Samuel L; Araújo, Simara S; Hengge, Alvan C; Brandão, Tiago A S; Nagem, Ronaldo A P

    2016-09-27

    The salicylaldehyde dehydrogenase (NahF) catalyzes the oxidation of salicylaldehyde to salicylate using NAD(+) as a cofactor, the last reaction of the upper degradation pathway of naphthalene in Pseudomonas putida G7. The naphthalene is an abundant and toxic compound in oil and has been used as a model for bioremediation studies. The steady-state kinetic parameters for oxidation of aliphatic or aromatic aldehydes catalyzed by 6xHis-NahF are presented. The 6xHis-NahF catalyzes the oxidation of aromatic aldehydes with large kcat/Km values close to 10(6) M(-1) s(-1). The active site of NahF is highly hydrophobic, and the enzyme shows higher specificity for less polar substrates than for polar substrates, e.g., acetaldehyde. The enzyme shows α/β folding with three well-defined domains: the oligomerization domain, which is responsible for the interlacement between the two monomers; the Rossmann-like fold domain, essential for nucleotide binding; and the catalytic domain. A salicylaldehyde molecule was observed in a deep pocket in the crystal structure of NahF where the catalytic C284 and E250 are present. Moreover, the residues G150, R157, W96, F99, F274, F279, and Y446 were thought to be important for catalysis and specificity for aromatic aldehydes. Understanding the molecular features responsible for NahF activity allows for comparisons with other aldehyde dehydrogenases and, together with structural information, provides the information needed for future mutational studies aimed to enhance its stability and specificity and further its use in biotechnological processes.

  16. GRE2 from Scheffersomyces stipitis as an aldehyde reductase contributes tolerance to aldehyde inhibitors derived from lignocellulosic biomass.

    PubMed

    Wang, Xu; Ma, Menggen; Liu, Z Lewis; Xiang, Quanju; Li, Xi; Liu, Na; Zhang, Xiaoping

    2016-08-01

    Scheffersomyces (Pichia) stipitis is one of the most promising yeasts for industrial bioethanol production from lignocellulosic biomass. S. stipitis is able to in situ detoxify aldehyde inhibitors (such as furfural and 5-hydroxymethylfurfural (HMF)) to less toxic corresponding alcohols. However, the reduction enzymes involved in this reaction remain largely unknown. In this study, we reported that an uncharacterized open reading frame PICST_72153 (putative GRE2) from S. stipitis was highly induced in response to furfural and HMF stresses. Overexpression of this gene in Saccharomyces cerevisiae improved yeast tolerance to furfural and HMF. GRE2 was identified as an aldehyde reductase which can reduce furfural to FM with either NADH or NADPH as the co-factor and reduce HMF to FDM with NADPH as the co-factor. This enzyme can also reduce multiple aldehydes to their corresponding alcohols. Amino acid sequence analysis indicated that it is a member of the subclass "intermediate" of the short-chain dehydrogenase/reductase (SDR) superfamily. Although GRE2 from S. stipitis is similar to GRE2 from S. cerevisiae in a three-dimensional structure, some differences were predicted. GRE2 from S. stipitis forms loops at D133-E137 and T143-N145 locations with two α-helices at E154-K157 and E252-A254 locations, different GRE2 from S. cerevisiae with an α-helix at D133-E137 and a β-sheet at T143-N145 locations, and two loops at E154-K157 and E252-A254 locations. This research provided guidelines for the study of other SDR enzymes from S. stipitis and other yeasts on tolerant mechanisms to aldehyde inhibitors derived from lignocellulosic biomass. PMID:27003269

  17. Oligonucleotide-conjugated thiazole orange probes as "light-up" probes for messenger ribonucleic acid molecules in living cells.

    PubMed

    Privat, E; Melvin, T; Asseline, U; Vigny, P

    2001-10-01

    "Light-up" probes, icosa-alpha-thymidylate-thiazole orange conjugates, for the in situ time-resolved detection of messenger ribonucleic acid (mRNA) in living cells are evaluated. Upon annealing with polyA in aqueous solutions, the icosa-alpha-thymidylate-thiazole orange conjugates were shown to be up to 15 times more fluorescent. Microinjection of these probes into adherent fibroblasts resulted in high yields of hybridization and fluorescent signals. Incubation of cells in the presence of these probes resulted in facile internalization of the probe and similar painting of the messenger RNA in the nuclear and cytosolic regions.

  18. Role of Aldose Reductase in the Metabolism and Detoxification of Carnosine-Acrolein Conjugates*

    PubMed Central

    Baba, Shahid P.; Hoetker, Joseph David; Merchant, Michael; Klein, Jon B.; Cai, Jian; Barski, Oleg A.; Conklin, Daniel J.; Bhatnagar, Aruni

    2013-01-01

    Oxidation of unsaturated lipids generates reactive aldehydes that accumulate in tissues during inflammation, ischemia, or aging. These aldehydes form covalent adducts with histidine-containing dipeptides such as carnosine and anserine, which are present in high concentration in skeletal muscle, heart, and brain. The metabolic pathways involved in the detoxification and elimination of these conjugates are, however, poorly defined, and their significance in regulating oxidative stress is unclear. Here we report that conjugates of carnosine with aldehydes such as acrolein are produced during normal metabolism and excreted in the urine of mice and adult human non-smokers as carnosine-propanols. Our studies show that the reduction of carnosine-propanals is catalyzed by the enzyme aldose reductase (AR). Carnosine-propanals were converted to carnosine-propanols in the lysates of heart, skeletal muscle, and brain tissue from wild-type (WT) but not AR-null mice. In comparison with WT mice, the urinary excretion of carnosine-propanols was decreased in AR-null mice. Carnosine-propanals formed covalent adducts with nucleophilic amino acids leading to the generation of carnosinylated proteins. Deletion of AR increased the abundance of proteins bound to carnosine in skeletal muscle, brain, and heart of aged mice and promoted the accumulation of carnosinylated proteins in hearts subjected to global ischemia ex vivo. Perfusion with carnosine promoted post-ischemic functional recovery in WT but not in AR-null mouse hearts. Collectively, these findings reveal a previously unknown metabolic pathway for the removal of carnosine-propanal conjugates and suggest a new role of AR as a critical regulator of protein carnosinylation and carnosine-mediated tissue protection. PMID:23928303

  19. Conjugate and method for forming aminomethyl phosphorus conjugates

    DOEpatents

    Katti, Kattesh V.; Berning, Douglas E.; Volkert, Wynn A.; Ketring, Alan R.; Churchill, Robert

    1999-01-01

    A method of forming phosphine-amine conjugates includes reacting a hydroxymethyl phosphine group of an amine-free first molecule with at least one free amine group of a second molecule to covalently bond the first molecule with the second molecule through an aminomethyl phosphorus linkage and the conjugates formed thereby.

  20. A novel 4 S [3H]beta-naphthoflavone-binding protein in liver cytosol of female Sprague-Dawley rats treated with aryl hydrocarbon receptor agonists.

    PubMed Central

    Brauze, D; Malejka-Giganti, D

    2000-01-01

    -induced 4 S protein, whereas several PAHs including B[a]P and benzo[e]pyrene were only weak competitors. The increased [(3)H]beta-NF binding was not associated with glycine N-methyltransferase activity. Hence, the 4 S [(3)H]beta-NF-binding protein described herein differs from the constitutive 4 S PAH-binding protein of rat liver cytosols in the inducibility by beta-NF and 3-MC, ligand-binding characteristics, and lack of glycine N-methyltransferase activity. Gel filtration on Sephacryl of liver cytosols from beta-NF-treated rats indicated a molecular mass of approximately 42 kDa for [(3)H]beta-NF-bound protein and suggested that it was derived from a large mass component that before the radioligand binding was eluted with the void volume of the gel and sedimented in a 7 S fraction of the sucrose gradient. The [(3)H]beta-NF binding activity was not eluted with glutathione S-transferase Ya, aldehyde-3-dehydrogenase or DT-diaphorase [NAD(P)H: quinone oxidoreductase] activities, which are AhR-controlled and beta-NF-inducible. Further studies are needed to determine the identity and function of this novel protein which may be involved either directly or indirectly (as a carrier protein) in xenobiotic metabolism in vivo. PMID:10769184

  1. Construction of expression system of rabbit aldehyde oxidase cDNA for the clarification of species differences.

    PubMed

    Liu, Ping; Liang, Sun; Wang, Ben-Jie; Guo, Rui-Chen

    2009-01-01

    A remarkably large species difference in cinchonidine oxidation activity catalyzed by aldehyde oxidase (AO) has been known, in particular between rabbit and monkey. As the first step in clarifying the phenomenon from the view point of structures of the active site, we attempted to construct an expression system of rabbit AO cDNA. The nucleotide sequences of cloned full-length rabbit AO cDNA were determined and confirmed to agree completely with those of genome DNA. The expression system in Escherichia coli was constructed in reference to the previously established method for monkey AO. Both expressed rabbit and monkey AO proteins correctly reproduced the remarkable species differences observed in their liver cytosols towards cinchonidine and methotrexate. Namely, the expressed rabbit AO protein showed extremely high activities than did that of monkey AO. A difference in the structure of the active site might be responsible for the substrate-dependent species difference towards the relatively bulky molecules of cinchonidine and methotrexate. The use of molecular biology techniques will be very useful to verify the hypothesis.

  2. Microsomal aldehyde dehydrogenase is localized to the endoplasmic reticulum via its carboxyl-terminal 35 amino acids

    PubMed Central

    1994-01-01

    Rat microsomal aldehyde dehydrogenase (msALDH) has no amino-terminal signal sequence, but instead it has a characteristic hydrophobic domain at the carboxyl terminus (Miyauchi, K., R. Masaki, S. Taketani, A. Yamamoto, A. Akayama, and Y. Tashiro. 1991. J. Biol. Chem. 266:19536- 19542). This membrane-bound enzyme is a useful model protein for studying posttranslational localization to its final destination. When expressed from cDNA in COS-1 cells, wild-type msALDH is localized exclusively in the well-developed ER. The removal of the hydrophobic domain results in the cytosolic localization of truncated proteins, thus suggesting that the portion is responsible for membrane anchoring. The last 35 amino acids of msALDH, including the hydrophobic domain, are sufficient for targeting of E. coli beta-galactosidase to the ER membrane. Further studies using chloramphenicol acetyltransferase fusion proteins suggest that two hydrophilic sequences on either side of the hydrophobic domain play an important role in ER targeting. PMID:8089174

  3. Circadian oscillations of cytosolic and chloroplastic free calcium in plants

    NASA Technical Reports Server (NTRS)

    Johnson, C. H.; Knight, M. R.; Kondo, T.; Masson, P.; Sedbrook, J.; Haley, A.; Trewavas, A.

    1995-01-01

    Tobacco and Arabidopsis plants, expressing a transgene for the calcium-sensitive luminescent protein apoaequorin, revealed circadian oscillations in free cytosolic calcium that can be phase-shifted by light-dark signals. When apoaequorin was targeted to the chloroplast, circadian chloroplast calcium rhythms were likewise observed after transfer of the seedlings to constant darkness. Circadian oscillations in free calcium concentrations can be expected to control many calcium-dependent enzymes and processes accounting for circadian outputs. Regulation of calcium flux is therefore fundamental to the organization of circadian systems.

  4. Multielement analysis of metal-binding proteins in cytosol fractions.

    PubMed

    Bray, J T; Webb, L A; Reilly, F J

    1983-06-01

    The distribution of 24 elements among the cytosol protein fractions was determined for specimens of the bivalve mollusc Macoma balthica obtained from three estuarine locations subject to varying levels of metal pollution and on specimens of Rangia cuneata from three areas subject to varying degrees of thermal pollution. Of the 24 elements examined 15 occurred at levels above detection limits and in association with one or more of four distinct protein fractions. Levels of Ag and Cu associated with high molecular weight proteins and with "metallothionein-like" proteins permitted identification of those Macoma balthica specimens exposed to the greatest degree of metal stress.

  5. New scavenger resin for the reversible linking and monoprotection of functionalized aromatic aldehydes.

    PubMed

    Zhu, Mingzhao; Ruijter, Eelco; Wessjohann, Ludger A

    2004-10-28

    [reaction: see text] Polymer-supported benzylhydrazines were synthesized using poly(ethylene glycol) acrylamide (PEGA) resin. They can be used to scavenge electrophiles reactive with hydrazine. Especially aromatic aldehydes can be captured selectively, monoprotected, and reversibly linked in the presence of other functional groups, including electrophilic ones. Various reactions can be performed on these protectively linked aldehydes, which afterward can be released either with full restoration of the aldehyde function or, alternatively, with simultaneous conversion.

  6. Ionic liquid-supported aldehyde: a highly efficient scavenger for primary amines.

    PubMed

    Muthayala, Manoj Kumar; Kumar, Anil

    2012-01-01

    Novel aldehyde-functionalized ionic liquids have been synthesized and used as scavengers for primary amines in the synthesis of secondary amines. The yields of secondary amines are high (82-90%) with high purity. The advantages of the protocol over that with a polymer-supported aldehyde scavenger are the shorter reaction time, the homogeneous reaction medium, the high level of loading of the aldehyde group, easy monitoring of reaction, and characterization of intermediates.

  7. Ni-Catalyzed Dehydrogenative Cross-Coupling: Direct Transformation of Aldehydes to Esters and Amides

    PubMed Central

    Whittaker, Aaron M.; Dong, Vy M.

    2015-01-01

    By exploring a new mode of Ni-catalyzed cross-coupling, we have developed a protocol to transform both aromatic and aliphatic aldehydes into either esters or amides directly. The success of this oxidative coupling depends on the appropriate choice of catalyst and organic oxidant, including the use of either α,α,α-trifluoroacetophenone or excess aldehyde. We present mechanistic data that supports a catalytic cycle involving oxidative addition into the aldehyde C–H bond. PMID:25424967

  8. Nickel-catalyzed dehydrogenative cross-coupling: direct transformation of aldehydes into esters and amides.

    PubMed

    Whittaker, Aaron M; Dong, Vy M

    2015-01-19

    By exploring a new mode of nickel-catalyzed cross-coupling, a method to directly transform both aromatic and aliphatic aldehydes into either esters or amides has been developed. The success of this oxidative coupling depends on the appropriate choice of catalyst and organic oxidant, including the use of either α,α,α-trifluoroacetophenone or excess aldehyde. Mechanistic data that supports a catalytic cycle involving oxidative addition into the aldehyde C-H bond is also presented. PMID:25424967

  9. Betaine aldehyde, betaine, and choline levels in rat livers during ethanol metabolism.

    PubMed

    Chern, M K; Gage, D A; Pietruszko, R

    2000-12-01

    Betaine aldehyde levels were determined in rat livers following 4 weeks of ethanol feeding, employing the Lieber-De Carli liquid diet. The results showed that the levels of betaine aldehyde are unaffected by alcohol feeding to rats. These levels in both experimental and control animals were found to be quite low, 5.5 nmol/g liver. Betaine aldehyde levels have not been determined previously in mammalian liver because of methodological difficulties. This investigation employed fast atom bombardment-mass spectroscopy to determine the levels of betaine aldehyde, betaine, and choline. The decrease in betaine levels following ethanol administration confirmed the results of other investigators. Choline levels determined during this investigation were lower than previously reported. The reason for starting this investigation was the fact that the enzyme that catalyzes betaine aldehyde dehydrogenation to betaine, which is distributed in both mitochondria and the cytoplasm, was found to also metabolize acetaldehyde with K(m) and V(max) values lower than those for betaine aldehyde. Thus, it appeared likely that the metabolism of acetaldehyde during ethanol metabolism might inhibit betaine aldehyde conversion to betaine and thereby result in decreased betaine levels (Barak et al., Alcohol 13: 395-398, 1996). The fact that betaine aldehyde levels in alcohol-fed animals were similar to those in controls demonstrates that competition between acetaldehyde and betaine aldehyde for the same enzyme does not occur. This complete lack of competition suggests that betaine aldehyde dehydrogenase in the mitochondrial matrix may totally metabolize betaine aldehyde to betaine without any involvement of cytoplasmic betaine aldehyde dehydrogenase. PMID:11077045

  10. Antibody-gold cluster conjugates

    DOEpatents

    Hainfeld, J.F.

    1988-06-28

    Antibody- or antibody fragment-gold cluster conjugates are shown wherein the conjugate size can be about 5.0 nm. Methods and reagents are disclosed in which antibodies or Fab' fragments thereof are covalently bound to a stable cluster of gold atoms. 2 figs.

  11. Development of soluble ester-linked aldehyde polymers for proteomics.

    PubMed

    Beaudette, Patrick; Rossi, Nicholas A A; Huesgen, Pitter F; Yu, Xifei; Shenoi, Rajesh A; Doucet, Alain; Overall, Christopher M; Kizhakkedathu, Jayachandran N

    2011-09-01

    High molecular weight hyperbranched polyglycerol (HPG) was selected for development as a soluble polymer support for the targeted selection and release of primary-amine containing peptides from a complex mixture. HPG has been functionalized with ester-linked aldehyde groups that can bind primary-amine containing peptides via a reductive alkylation reaction. Once bound, the high molecular weight of the polymer facilitates separation from a complex peptide mixture by employing either a 30 kDa molecular weight cutoff membrane or precipitation in acetonitrile. Following the removal of unbound peptides and reagents, subsequent hydrolysis of the ester linker releases the bound peptide into solution for analysis by mass spectrometry. Released peptides retain the linker moiety and are therefore characteristically mass-shifted. Four water-soluble cleavable aldehyde polymers (CAP1, CAP2, CAP3, and CAP4) ranging in types of linker groups, length of the linker groups, have been prepared and characterized, each demonstrating the ability to selectively enrich and sequence primary-amine peptides from a complex human proteome containing blocked (dimethylated amine) and unblocked (primary amine) peptides. The polymers have very low nonspecific peptide-binding properties while possessing significantly more reactive groups per milligram of the support than commercially available resins. The polymers exhibit a range of reactivities and binding capacities that depend on the type of linker group between the aldehyde group and the polymer. Using various linker structures, we also probed the mechanism of the observed dehydration of hydrolyzed peptides during matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis.

  12. Interstellar Aldehydes and their corresponding Reduced Alcohols: Interstellar Propanol?

    NASA Astrophysics Data System (ADS)

    Etim, Emmanuel; Chakrabarti, Sandip Kumar; Das, Ankan; Gorai, Prasanta; Arunan, Elangannan

    2016-07-01

    There is a well-defined trend of aldehydes and their corresponding reduced alcohols among the known interstellar molecules; methanal (CH_2O) and methanol (CH_3OH); ethenone (C_2H_2O) and vinyl alcohol (CH_2CHOH); ethanal (C_2H_4O) and ethanol(C_2H_5OH); glycolaldehyde (C_2H_4O_2) and ethylene glycol(C_2H_6O_2). The reduced alcohol of propanal (CH_3CH_2CHO) which is propanol (CH_3CH_2CH_2OH) has not yet been observed but its isomer; ethyl methyl ether (CH_3CH_2OCH_3) is a known interstellar molecule. In this article, different studies are carried out in investigating the trend between aldehydes and their corresponding reduced alcohols and the deviation from the trend. Kinetically and with respect to the formation route, alcohols could have been produced from their corresponding reduced aldehydes via two successive hydrogen additions. This is plausible because of (a) the unquestionable high abundance of hydrogen, (b) presence of energy sources within some of the molecular clouds and (c) the ease at which successive hydrogen addition reaction occurs. In terms of stability, the observed alcohols are thermodynamically favorable as compared to their isomers. Regarding the formation process, the hydrogen addition reactions are believed to proceed on the surface of the interstellar grains which leads to the effect of interstellar hydrogen bonding. From the studies, propanol and propan-2-ol are found to be more strongly attached to the surface of the interstellar dust grains which affects its overall gas phase abundance as compared to its isomer ethyl methyl ether which has been observed.

  13. Bioreduction of aldehydes and ketones using Manihot species.

    PubMed

    Machado, Luciana L; Souza, João Sammy N; de Mattos, Marcos Carlos; Sakata, Solange K; Cordell, Geoffrey A; Lemos, Telma L G

    2006-08-01

    Biocatalysis constitutes an important tool in organic synthesis, especially for the preparation of chiral molecules of biological interest. A series of aliphatic and aromatic aldehydes and two ketones were reduced using plant cell preparations from Manihot esculenta and Manihot dulcis roots. The reduced products were typically obtained in excellent yields (80-96%), and with excellent enantiomeric excess (94-98%), except for vanillin. Esters, a nitrile, and an amide were also examined, but were not reduced. Preliminary conversion rate studies are reported. This is the first attempt to perform the biotransformation of carbonyl compounds using Manihot species. PMID:16603212

  14. Some properties of aldehyde dehydrogenase from sheep liver mitochondria.

    PubMed Central

    Hart, G J; Dickinson, F M

    1977-01-01

    Aldehyde dehydrogenase from sheep liver mitochondria was purified to homogeneity as judged by electrophoresis on polyacrylamide gels, and by sedimentation-equilibrium experiments in the analytical ultracentrifuge. The enzyme has a molecular weight of 198000 and a subunit size of 48000, indicating that the molecule is a tetramer. Fluorescence and spectrophotometric titrations indicate that each subunit can bind 1 molecule of NADH. Enzymic activity is completely blocked by reaction of 4mol of 5,5'-dithiobis-(2-nitrobenzoate)/mol of enzyme. Excess of disulfiram or iodoacetamide decreases activity to only 50% of the control value, and only two thiol groups per molecule are apparently modified by these reagents. PMID:194582

  15. [Activity of aldehyde scavenger enzymes in the heart of rats of different age during immobilized stress].

    PubMed

    Grabovetskaia, E R; Davydov, V V

    2009-01-01

    This study was made to determine the activity of aldehyde scavenger enzymes in the heart's postmitochondrial fraction of rats of different age during immobilization stress. Our study demonstrated, that immobilization of 1.5-, 2- and 12-month rats was accompanied by inhibiting activity of aldehyde dehydrogenase and aldehyde reductase. At the same time we observed an increase in glutathione transferase activity in immobilized 1.5-month-old rats and that in reductase activity in 24-month-old rats. The revealed changes can lead to a decrease in the rate of endogenous aldehyde utilization in the heart during stress at puberty.

  16. [Pollution Characteristics of Aldehydes and Ketones Compounds in the Exhaust of Beijing Typical Restaurants].

    PubMed

    Cheng, Jing-chen; Cui, Tong; He, Wan-qing; Nie, Lei; Wang, Jun-ling; Pan, Tao

    2015-08-01

    Aldehydes and ketones compounds, as one of the components in the exhaust of restaurants, are a class of volatile organic compounds (VOCs) with strong chemical reactivity. However, there is no systematic study on aldehydes and ketones compounds in the exhaust of restaurants. To further clarify the food source emission levels of aldehydes and ketones compounds and controlling measures, to access city group catering VOCs emissions control decision-making basis, this study selected 8 Beijing restaurants with different types. The aldehydes and ketones compounds were sampled using DNPH-silica tube, and then ultra performance liquid chromatography was used for quantitative measurement. The aldehydes and ketones concentrations of reference volume condition from 8 restaurants in descending order were Roasted Duck restaurant, Chinese Style Barbecue, Home Dishes, Western Fast-food, School Canteen, Chinese Style Fast-food, Sichuan Cuisine, Huaiyang Cuisine. The results showed that the range of aldehydes and ketones compounds (C1-C9) concentrations of reference volume condition in the exhaust of restaurants was 115.47-1035.99 microg x m(-3). The composition of aldehydes and ketones compounds in the exhaust of sampled restaurants was obviously different. The percentages of C1-C3 were above 40% in the exhaust from Chinese style restaurants. Fast food might emit more C4-C9 aldehydes and ketones compounds. From the current situation of existing aldehydes and ketones compounds control, the removal efficiency of high voltage electrostatic purifiers widely used in Beijing is limited.

  17. Sulfation of ractopamine and salbutamol by the human cytosolic sulfotransferases

    PubMed Central

    Ko, KyoungA; Kurogi, Katsuhisa; Davidson, Garrett; Liu, Ming-Yih; Sakakibara, Yoichi; Suiko, Masahito; Liu, Ming-Cheh

    2012-01-01

    Feed additives such as ractopamine and salbutamol are pharmacologically active compounds, acting primarily as β-adrenergic agonists. This study was designed to investigate whether the sulfation of ractopamine and salbutamol may occur under the metabolic conditions and to identify the human cytosolic sulfotransferases (SULTs) that are capable of sulfating two major feed additive compounds, ractopamine and salbutamol. A metabolic labelling study showed the generation and release of [35S]sulfated ractopamine and salbutamol by HepG2 human hepatoma cells labelled with [35S]sulfate in the presence of these two compounds. A systematic analysis using 11 purified human SULTs revealed SULT1A3 as the major SULT responsible for the sulfation of ractopamine and salbutamol. The pH dependence and kinetic parameters were analyzed. Moreover, the inhibitory effects of ractopamine and salbutamol on SULT1A3-mediated dopamine sulfation were investigated. Cytosol or S9 fractions of human lung, liver, kidney and small intestine were examined to verify the presence of ractopamine-/salbutamol-sulfating activity in vivo. Of the four human organs, the small intestine displayed the highest activity towards both compounds. Collectively, these results imply that the sulfation mediated by SULT1A3 may play an important role in the metabolism and detoxification of ractopamine and salbutamol. PMID:22763752

  18. Cell-to-cell propagation of infectious cytosolic protein aggregates

    PubMed Central

    Hofmann, Julia P.; Denner, Philip; Nussbaum-Krammer, Carmen; Kuhn, Peer-Hendrik; Suhre, Michael H.; Scheibel, Thomas; Lichtenthaler, Stefan F.; Schätzl, Hermann M.; Bano, Daniele; Vorberg, Ina M.

    2013-01-01

    Prions are self-templating protein conformers that replicate by recruitment and conversion of homotypic proteins into growing protein aggregates. Originally identified as causative agents of transmissible spongiform encephalopathies, increasing evidence now suggests that prion-like phenomena are more common in nature than previously anticipated. In contrast to fungal prions that replicate in the cytoplasm, propagation of mammalian prions derived from the precursor protein PrP is confined to the cell membrane or endocytic vesicles. Here we demonstrate that cytosolic protein aggregates can also behave as infectious entities in mammalian cells. When expressed in the mammalian cytosol, protein aggregates derived from the prion domain NM of yeast translation termination factor Sup35 persistently propagate and invade neighboring cells, thereby inducing a self-perpetuating aggregation state of NM. Cell contact is required for efficient infection. Aggregates can also be induced in primary astrocytes, neurons, and organotypic cultures, demonstrating that this phenomenon is not specific to immortalized cells. Our data have important implications for understanding prion-like phenomena of protein aggregates associated with human diseases and for the growing number of amyloidogenic proteins discovered in mammals. PMID:23509289

  19. Novel cytosolic allergens of Aspergillus fumigatus identified from germinating conidia.

    PubMed

    Singh, Bharat; Sharma, Gainda L; Oellerich, Michael; Kumar, Ram; Singh, Seema; Bhadoria, Dharam P; Katyal, Anju; Reichard, Utz; Asif, Abdul R

    2010-11-01

    Aspergillus fumigatus is the common cause of allergic broncho-pulmonary aspergillosis (ABPA) and most of the allergens have been described from its secreted fraction. In the present investigation, germinating conidial cytosolic proteins of A. fumigatus were extracted from a 16 h culture. The proteome from this fraction was developed, and immuno-blots were generated using pooled ABPA patients' sera. Well separated Immunoglobulin-E (IgE) and Immunoglobulin-G (IgG) reactive spots were picked from corresponding 2DE gels and subjected to mass spectrometric analysis. As a result, 66 immuno-reactive proteins were identified from two geographically different strains (190/96 and DAYA) of A. fumigatus. Only 3 out of 66 proteins reacted with IgG, and the remaining 63 proteins were found to be IgE reactive. These 63 IgE-reactive cytosolic proteins from germinating conidia included 2 already known (Asp f12 and Asp f22) and 4 predicted allergens (Hsp88, Hsp70, malate dehydrogenase, and alcohol dehydrogenase) based on their homology with other known fungal allergens. In view of this, the panel of presently identified IgE-reactive novel proteins holds the potential of providing a basis for the wider diagnostic application in assay for allergic aspergillosis. We could demonstrate that recombinantly expressed proteins from this panel showed consistent reactivity with IgE of individual sera of ABPA patients. The recombinantly expressed proteins may also be useful in desensitization therapy of allergic disorders including ABPA.

  20. Coupled ER to Golgi Transport Reconstituted with Purified Cytosolic Proteins

    PubMed Central

    Barlowe, Charles

    1997-01-01

    A cell-free vesicle fusion assay that reproduces a subreaction in transport of pro-α-factor from the ER to the Golgi complex has been used to fractionate yeast cytosol. Purified Sec18p, Uso1p, and LMA1 in the presence of ATP and GTP satisfies the requirement for cytosol in fusion of ER-derived vesicles with Golgi membranes. Although these purified factors are sufficient for vesicle docking and fusion, overall ER to Golgi transport in yeast semi-intact cells depends on COPII proteins (components of a membrane coat that drive vesicle budding from the ER). Thus, membrane fusion is coupled to vesicle formation in ER to Golgi transport even in the presence of saturating levels of purified fusion factors. Manipulation of the semi-intact cell assay is used to distinguish freely diffusible ER- derived vesicles containing pro-α-factor from docked vesicles and from fused vesicles. Uso1p mediates vesicle docking and produces a dilution resistant intermediate. Sec18p and LMA1 are not required for the docking phase, but are required for efficient fusion of ER- derived vesicles with the Golgi complex. Surprisingly, elevated levels of Sec23p complex (a subunit of the COPII coat) prevent vesicle fusion in a reversible manner, but do not interfere with vesicle docking. Ordering experiments using the dilution resistant intermediate and reversible Sec23p complex inhibition indicate Sec18p action is required before LMA1 function. PMID:9382859

  1. Non Linear Conjugate Gradient

    2006-11-17

    Software that simulates and inverts electromagnetic field data for subsurface electrical properties (electrical conductivity) of geological media. The software treats data produced by a time harmonic source field excitation arising from the following antenna geometery: loops and grounded bipoles, as well as point electric and magnetic dioples. The inversion process is carried out using a non-linear conjugate gradient optimization scheme, which minimizes the misfit between field data and model data using a least squares criteria.more » The software is an upgrade from the code NLCGCS_MP ver 1.0. The upgrade includes the following components: Incorporation of new 1 D field sourcing routines to more accurately simulate the 3D electromagnetic field for arbitrary geologic& media, treatment for generalized finite length transmitting antenna geometry (antennas with vertical and horizontal component directions). In addition, the software has been upgraded to treat transverse anisotropy in electrical conductivity.« less

  2. Generalized conjugate gradient squared

    SciTech Connect

    Fokkema, D.R.; Sleijpen, G.L.G.

    1994-12-31

    In order to solve non-symmetric linear systems of equations, the Conjugate Gradient Squared (CGS) is a well-known and widely used iterative method. In practice the method converges fast, often twice as fast as the Bi-Conjugate Gradient method. This is what you may expect, since CGS uses the square of the BiCG polynomial. However, CGS may suffer from its erratic convergence behavior. The method may diverge or the approximate solution may be inaccurate. BiCGSTAB uses the BiCG polynomial and a product of linear factors in an attempt to smoothen the convergence. In many cases, this has proven to be very effective. Unfortunately, the convergence of BiCGSTAB may stall when a linear factor (nearly) degenerates. BiCGstab({ell}) is designed to overcome this degeneration of linear factors. It generalizes BiCGSTAB and uses both the BiCG polynomial and a product of higher order factors. Still, CGS may converge faster than BiCGSTAB or BiCGstab({ell}). So instead of using a product of linear or higher order factors, it may be worthwhile to look for other polynomials. Since the BiCG polynomial is based on a three term recursion, a natural choice would be a polynomial based on another three term recursion. Possibly, a suitable choice of recursion coefficients would result in method that converges faster or as fast as CGS, but less erratic. It turns out that an algorithm for such a method can easily be formulated. One particular choice for the recursion coefficients leads to CGS. Therefore one could call this algorithm generalized CGS. Another choice for the recursion coefficients leads to BiCGSTAB. It is therefore possible to mix linear factors and some polynomial based on a three term recursion. This way one may get the best of both worlds. The authors will report on their findings.

  3. Conjugation of antibodies to gold nanorods through Fc portion: synthesis and molecular specific imaging

    PubMed Central

    Joshi, Pratixa P.; Yoon, Soon Joon; Hardin, William G.; Emelianov, Stanislav; Sokolov, Konstantin V.

    2013-01-01

    Anisotropic gold nanorods provide a convenient combination of properties, such as tunability of plasmon resonances and strong extinction cross-sections in the near-infrared to red spectral region. These properties have created significant interest in the development of antibody conjugation methods for synthesis of targeted nanorods for a number of biomedical applications, including molecular specific imaging and therapy. Previously published conjugation approaches have achieved molecular specificity. However, the current conjugation methods have several downsides including low stability and potential cytotoxicity of bioconjugates that are produced by electrostatic interactions as well as lack of control over antibody orientation during covalent conjugation. Here we addressed these shortcomings by introducing directional antibody conjugation to the gold nanorod surface. The directional conjugation is achieved through the carbohydrate moiety, which is located on one of the heavy chains of the Fc portion of most antibodies. The carbohydrate is oxidized under mild conditions to a hydrazide reactive aldehyde group. Then, a heterofunctional linker with hydrazide and dithiol groups is used to attach antibodies to gold nanorods. The directional conjugation approach was characterized using electron microscopy, zeta potential and extinction spectra. We also determined spectral changes associated with nanorod aggregation; these spectral changes can be used as a convenient quality control of nanorod bioconjugates. Molecular specificity of the synthesized antibody targeted nanorods was demonstrated using hyperspectral optical and photoacoustic imaging of cancer cell culture models. Additionally, we observed characteristic changes in optical spectra of molecular specific nanorods after their interactions with cancer cells; the observed spectral signatures can be explored for sensitive cancer detection. PMID:23631707

  4. The importance of cytosolic glutamine synthetase in nitrogen assimilation and recycling

    SciTech Connect

    Bernard, S.M.; Habash, D.Z.

    2009-07-02

    Glutamine synthetase assimilates ammonium into amino acids, thus it is a key enzyme for nitrogen metabolism. The cytosolic isoenzymes of glutamine synthetase assimilate ammonium derived from primary nitrogen uptake and from various internal nitrogen recycling pathways. In this way, cytosolic glutamine synthetase is crucial for the remobilization of protein-derived nitrogen. Cytosolic glutamine synthetase is encoded by a small family of genes that are well conserved across plant species. Members of the cytosolic glutamine synthetase gene family are regulated in response to plant nitrogen status, as well as to environmental cues, such as nitrogen availability and biotic/abiotic stresses. The complex regulation of cytosolic glutamine synthetase at the transcriptional to post-translational levels is key to the establishment of a specific physiological role for each isoenzyme. The diverse physiological roles of cytosolic glutamine synthetase isoenzymes are important in relation to current agricultural and ecological issues.

  5. Aldehyde dehydrogenase 2 (ALDH2) rescues myocardial ischaemia/reperfusion injury: role of autophagy paradox and toxic aldehyde

    PubMed Central

    Ma, Heng; Guo, Rui; Yu, Lu; Zhang, Yingmei; Ren, Jun

    2011-01-01

    Aims The present study was designed to examine the mechanism involved in mitochondrial aldehyde dehydrogenase (ALDH2)-induced cardioprotection against ischaemia/reperfusion (I/R) injury with a focus on autophagy. Methods Wild-type (WT), ALDH2 overexpression, and knockout (KO) mice (n = 4–6 for each index measured) were subjected to I/R, and myocardial function was assessed using echocardiographic, Langendroff, and edge-detection systems. Western blotting was used to evaluate AMP-dependent protein kinase (AMPK), Akt, autophagy, and the AMPK/Akt upstream signalling LKB1 and PTEN. Results ALDH2 overexpression and KO significantly attenuated and accentuated, respectively, infarct size, factional shortening, and recovery of post-ischaemic left ventricular function following I/R as well as hypoxia/reoxygenation-induced cardiomyocyte contractile dysfunction. Autophagy was induced during ischaemia and remained elevated during reperfusion. ALDH2 significantly promoted autophagy during ischaemia, which was accompanied by AMPK activation and mammalian target of rapamycin (mTOR) inhibition. On the contrary, ALDH2 overtly inhibited autophagy during reperfusion accompanied by the activation of Akt and mTOR. Inhibition and induction of autophagy mitigated ALDH2-induced protection against cell death in hypoxia and reoxygenation, respectively. In addition, levels of the endogenous toxic aldehyde 4-hydroxy-2-nonenal (4-HNE) were elevated by ischaemia and reperfusion, which was abrogated by ALDH2. Furthermore, ALDH2 ablated 4-HNE-induced cardiomyocyte dysfunction and protein damage, whereas 4-HNE directly decreased pan and phosphorylated LKB1 and PTEN expression. Conclusion Our data suggest a myocardial protective effect of ALDH2 against I/R injury possibly through detoxification of toxic aldehyde and a differential regulation of autophagy through AMPK- and Akt-mTOR signalling during ischaemia and reperfusion, respectively. PMID:20705694

  6. Current status of the cytosolic sulfotransferases in the metabolic activation of promutagens and procarcinogens.

    PubMed

    Banoglu, E

    2000-07-01

    Cytosolic sulfotransferases (SULT) catalyze the sulfation of structurally diverse drugs, endogenous compounds and xenobiotics. These reactions involve the transfer of a sulfuryl group from 3'-phosphoadenosine 5'-phosphosulfate (PAPS) to the hydroxyl/amino groups of acceptor molecules. Although sulfate conjugation is generally considered as a detoxication pathway producing more water-soluble and often less toxic metabolites, sulfation of certain classes of compounds produce sufficiently electrophilic metabolites that can covalently bind to cellular macromolecules, DNA and RNA. The important roles of electrophilic sulfate ester metabolites in the metabolic activation, mutagenicity and ultimate carcinogenicity of many xenobiotics have been considerably elucidated. Examples include the class of hydroxymethyl polycyclic aromatic hydrocarbons, allylic alcohols, N-hydroxy derivatives of carcinogenic arylamines and heterocyclic amines. Results obtained by many scientists during the last two decade correlate with a hypothesis that electrophilic sulfate esters may be the major ultimate carcinogenic forms of many, if not most, procarcinogens derived from benzylic/allylic alcohols and hydroxy arylamines. Careful analysis of these results suggest that the activities of human hydroxysteroid sulfotransferase (hHST), and a related form in rat liver, rat hydroxysteroid sulfotransferase a (STa), as well as aryl sulfotransferases both from rat and human liver, account for a substantial portion of the activation of benzylic/allylic alcohols in these species. Moreover, aryl sulfotransferases have also been indicated as the responsible SULT family in the bioactivation of hydroxy arylamines in the liver of different species including human. Molecular cloning of the individual sulfotransferases and expression of these individual forms in heterologous expression systems have allowed us to better understand the role of SULTs in the bioactivation of different procarcinogens and the form of

  7. Phase-II conjugation ability for PAH metabolism in amphibians: characteristics and inter-species differences.

    PubMed

    Ueda, Haruki; Ikenaka, Yoshinori; Nakayama, Shouta M M; Tanaka-Ueno, Tomoko; Ishizuka, Mayumi

    2011-10-01

    The present study examines amphibian metabolic activity - particularly conjugation - by analysis of pyrene (a four ring, polycyclic aromatic hydrocarbon) metabolites using high-performance liquid chromatography (HPLC) with fluorescence detector (FD), a mass spectrometry detector (MS) system and kinetic analysis of conjugation enzymes. Six amphibian species were exposed to pyrene (dissolved in water): African claw frog (Xenopus laevis); Tago's brown frog (Rana tagoi); Montane brown frog (Rana ornativentris); Wrinkled frog (Rana rugosa); Japanese newt (Cynops pyrrhogaster); and Clouded salamander (Hynobius nebulosus); plus one fish species, medaka (Oryzias latipes); and a fresh water snail (Clithon retropictus), and the resultant metabolites were collected. Identification of pyrene metabolites by HPLC and ion-trap MS system indicated that medaka mainly excreted pyrene-1-glucuronide (PYOG), while pyrene-1-sulfate (PYOS) was the main metabolite in all amphibian species. Pyrene metabolites in amphibians were different from those in invertebrate fresh water snails. Inter-species differences were also observed in pyrene metabolism among amphibians. Metabolite analysis showed that frogs relied more strongly on sulfate conjugation than did Japanese newts and clouded salamanders. Furthermore, urodelan amphibians, newts and salamanders, excreted glucose conjugates of pyrene that were not detected in the anuran amphibians. Kinetic analysis of conjugation by hepatic microsomes and cytosols indicated that differences in excreted metabolites reflected differences in enzymatic activities. Furthermore, pyrenediol (PYDOH) glucoside sulfate was detected in the Japanese newt sample. This novel metabolite has not been reported previously to this report, in which we have identified unique characteristics of amphibians in phase II pyrene metabolism.

  8. Aldehyde dehydrogenase 1A1 in stem cells and cancer

    PubMed Central

    Tomita, Hiroyuki; Tanaka, Kaori; Tanaka, Takuji; Hara, Akira

    2016-01-01

    The human genome contains 19 putatively functional aldehyde dehydrogenase (ALDH) genes, which encode enzymes critical for detoxification of endogenous and exogenous aldehyde substrates through NAD(P)+-dependent oxidation. ALDH1 has three main isotypes, ALDH1A1, ALDH1A2, and ALDH1A3, and is a marker of normal tissue stem cells (SC) and cancer stem cells (CSC), where it is involved in self-renewal, differentiation and self-protection. Experiments with murine and human cells indicate that ALDH1 activity, predominantly attributed to isotype ALDH1A1, is tissue- and cancer-specific. High ALDH1 activity and ALDH1A1 overexpression are associated with poor cancer prognosis, though high ALDH1 and ALDH1A1 levels do not always correlate with highly malignant phenotypes and poor clinical outcome. In cancer therapy, ALDH1A1 provides a useful therapeutic CSC target in tissue types that normally do not express high levels of ALDH1A1, including breast, lung, esophagus, colon and stomach. Here we review the functions and mechanisms of ALDH1A1, the key ALDH isozyme linked to SC populations and an important contributor to CSC function in cancers, and we outline its potential in future anticancer strategies. PMID:26783961

  9. Volatile aldehydes are promising broad-spectrum postharvest insecticides.

    PubMed

    Hammond, D G; Rangel, S; Kubo, I

    2000-09-01

    A variety of naturally occurring aldehydes common in plants have been evaluated for their insecticidal activity and for phytotoxicity to postharvest fruits, vegetables, and grains. Twenty-nine compounds were initially screened for their activity against aphids on fava bean leaf disks. Application under reduced pressure (partial vacuum) for the first quarter of fumigation increased insecticidal activity severalfold. The 11 best aldehydes were assayed against aphids placed under the third leaf of whole heads of iceberg lettuce using the same two-tier reduced-pressure regime, which caused no additional detriment to the commodity over fumigation at atmospheric pressure. Phytotoxicity to naked and wrapped iceburg lettuce, green and red table grapes, lemon, grapefruit, orange, broccoli, avocado, cabbage, pinto bean, and rice at doses that killed 100% of aphids was recorded for three promising fumigants: propanal, (E)-2-pentenal, and 2-methyl-(E)-2-butenal. These three compounds have excellent potential as affordable postharvest insect control agents, killing 100% of the aphids with little or no detectable harm to a majority of the commodities tested. Preliminary assays indicate that similar doses are also effective against mealybugs, thrips, and whitefly. PMID:10995371

  10. Modulation of therapy-induced senescence by reactive lipid aldehydes

    PubMed Central

    Flor, A C; Doshi, A P; Kron, S J

    2016-01-01

    Current understanding points to unrepairable chromosomal damage as the critical determinant of accelerated senescence in cancer cells treated with radiation or chemotherapy. Nonetheless, the potent senescence inducer etoposide not only targets topoisomerase II to induce DNA damage but also produces abundant free radicals, increasing cellular reactive oxygen species (ROS). Toward examining roles for DNA damage and oxidative stress in therapy-induced senescence, we developed a quantitative flow cytometric senescence assay and screened 36 redox-active agents as enhancers of an otherwise ineffective dose of radiation. While senescence failed to correlate with total ROS, the radiation enhancers, etoposide and the other effective topoisomerase inhibitors each produced high levels of lipid peroxidation. The reactive aldehyde 4-hydroxy-2-nonenal, a lipid peroxidation end product, was sufficient to induce senescence in irradiated cells. In turn, sequestering aldehydes with hydralazine blocked effects of etoposide and other senescence inducers. These results suggest that lipid peroxidation potentiates DNA damage from radiation and chemotherapy to drive therapy-induced senescence. PMID:27453792

  11. Toxic Diatom Aldehydes Affect Defence Gene Networks in Sea Urchins

    PubMed Central

    Varrella, Stefano; Ruocco, Nadia; Ianora, Adrianna; Bentley, Matt G.; Costantini, Maria

    2016-01-01

    Marine organisms possess a series of cellular strategies to counteract the negative effects of toxic compounds, including the massive reorganization of gene expression networks. Here we report the modulated dose-dependent response of activated genes by diatom polyunsaturated aldehydes (PUAs) in the sea urchin Paracentrotus lividus. PUAs are secondary metabolites deriving from the oxidation of fatty acids, inducing deleterious effects on the reproduction and development of planktonic and benthic organisms that feed on these unicellular algae and with anti-cancer activity. Our previous results showed that PUAs target several genes, implicated in different functional processes in this sea urchin. Using interactomic Ingenuity Pathway Analysis we now show that the genes targeted by PUAs are correlated with four HUB genes, NF-κB, p53, δ-2-catenin and HIF1A, which have not been previously reported for P. lividus. We propose a working model describing hypothetical pathways potentially involved in toxic aldehyde stress response in sea urchins. This represents the first report on gene networks affected by PUAs, opening new perspectives in understanding the cellular mechanisms underlying the response of benthic organisms to diatom exposure. PMID:26914213

  12. Direct electrochemistry of the Desulfovibrio gigas aldehyde oxidoreductase.

    PubMed

    Correia dos Santos, Margarida M; Sousa, Patrícia M P; Gonçalves, M Lurdes S; Romão, M João; Moura, Isabel; Moura, José J G

    2004-04-01

    This work reports on the direct electrochemistry of the Desulfovibrio gigas aldehyde oxidoreductase (DgAOR), a molybdenum enzyme of the xanthine oxidase family that contains three redox-active cofactors: two [2Fe-2S] centers and a molybdopterin cytosine dinucleotide cofactor. The voltammetric behavior of the enzyme was analyzed at gold and carbon (pyrolytic graphite and glassy carbon) electrodes. Two different strategies were used: one with the molecules confined to the electrode surface and a second with DgAOR in solution. In all of the cases studied, electron transfer took place, although different redox reactions were responsible for the voltammetric signal. From a thorough analysis of the voltammetric responses and the structural properties of the molecular surface of DgAOR, the redox reaction at the carbon electrodes could be assigned to the reduction of the more exposed iron cluster, [2Fe-2S] II, whereas reduction of the molybdopterin cofactor occurs at the gold electrode. Voltammetric results in the presence of aldehydes are also reported and discussed.

  13. Residual Particle Sizes of Evaporating Droplets: Ammonium Sulfate and Aldehydes

    NASA Astrophysics Data System (ADS)

    Sedehi, N.; Galloway, M. M.; De Haan, D. O.

    2012-12-01

    The reactions of carbonyls like glyoxal, methylglyoxal, and glycolaldehyde, with ammonium salts have been proposed as significant sources of atmospheric organic aerosol. Aerosol containing these compounds was generated in the laboratory using the Vibrating Orifice Aerosol Generator (VOAG). The particles were completely dried before they were measured using a SMPS system. The nonvolatile fraction of the resulting aerosol was measured. The drying times were varied between two and twenty minutes, and for ammonium sulfate and glyoxal reactions, minimum residual particle sizes were reached after 3.5 minutes. Reactions of glyoxal, glycolaldehyde, and methylglyoxal with ammonium sulfate appeared to have lower non-volatile fractions remaining at higher starting concentrations, suggesting that a constant 'excess volume,' likely water, was present in the residual particles that could not be evaporated even after 20 minutes of drying. These excess volumes were not observed in our previous experiments with aldehydes but no ammonium sulfate present. At the highest concentrations tested (100 uM), non-volatile fractions of aldehydes present in residual particles were 16 (±17) %, 41 (±28) %, and 17(±32) % for glyoxal, glycolaldehyde, and methylglyoxal, respectively.

  14. Indoor air chemistry: Formation of organic acids and aldehydes

    SciTech Connect

    Zhang, J.; Lioy, P.J. ||; Wilson, W.E.

    1994-12-31

    Laying emphasis on the formation of aldehydes and organic acids, the study has examined the gas-phase reactions of ozone with unsaturated VOCs. The formation of formaldehyde and formic acid was observed for all the three selected unsaturated VOCs: styrene, limonene, and 4-vinylcyclohexene. In addition, benzaldehyde was detected in the styrene-ozone-air reaction system, and acetic acid was also found in limonene-ozone-air system. The study has also examined the gas-phase reactions among formaldehyde, ozone, and nitrogen dioxide and found the formation of formic acid. The nitrate radical was suggested to play an important role in converting formaldehyde into formic acid. Experiments for all the reactions were conducted by using a 4.3 m{sup 3} Teflon chamber. Since the conditions for the reactions were similar to those for indoor environments, the results from the study can be implicated to real indoor situations and can be employed to support the findings and suggestions from the previous studies: certain aldehydes and organic acids could be generated by indoor chemistry.

  15. Spotting optimization for oligo microarrays on aldehyde-glass.

    PubMed

    Dawson, Erica D; Reppert, Amy E; Rowlen, Kathy L; Kuck, Laura R

    2005-06-15

    Low-density microarrays that utilize short oligos (<100 nt) for capture are highly attractive for use in diagnostic applications, yet these experiments require strict quality control and meticulous reproducibility. However, a survey of current literature indicates vast inconsistencies in the spotting and processing procedures. In this study, spotting and processing protocols were optimized for aldehyde-functionalized glass substrates. Figures of merit were developed for quantitative comparison of spot quality and reproducibility. Experimental variables examined included oligo concentration in the spotting buffer, composition of the spotting buffer, postspotting "curing" conditions, and postspotting wash conditions. Optimized conditions included the use of 3-4 microM oligo in a 3x standard saline citrate/0.05% sodium dodecyl sulfate/0.001% (3-[(3-cholamidopropyl) dimethylammonia]-1-propane sulfonate) spotting buffer, 24-h postspotting reaction at 100% relative humidity, and a four-step wash procedure. Evaluation of six types of aldehyde-functionalized glass substrates indicated that those manufactured by CEL Associates, Inc. yield the highest oligo coverage.

  16. Toxic Diatom Aldehydes Affect Defence Gene Networks in Sea Urchins.

    PubMed

    Varrella, Stefano; Romano, Giovanna; Costantini, Susan; Ruocco, Nadia; Ianora, Adrianna; Bentley, Matt G; Costantini, Maria

    2016-01-01

    Marine organisms possess a series of cellular strategies to counteract the negative effects of toxic compounds, including the massive reorganization of gene expression networks. Here we report the modulated dose-dependent response of activated genes by diatom polyunsaturated aldehydes (PUAs) in the sea urchin Paracentrotus lividus. PUAs are secondary metabolites deriving from the oxidation of fatty acids, inducing deleterious effects on the reproduction and development of planktonic and benthic organisms that feed on these unicellular algae and with anti-cancer activity. Our previous results showed that PUAs target several genes, implicated in different functional processes in this sea urchin. Using interactomic Ingenuity Pathway Analysis we now show that the genes targeted by PUAs are correlated with four HUB genes, NF-κB, p53, δ-2-catenin and HIF1A, which have not been previously reported for P. lividus. We propose a working model describing hypothetical pathways potentially involved in toxic aldehyde stress response in sea urchins. This represents the first report on gene networks affected by PUAs, opening new perspectives in understanding the cellular mechanisms underlying the response of benthic organisms to diatom exposure. PMID:26914213

  17. 4-Hydroxynonenal, an aldehydic product of membrane lipid peroxidation, impairs glutamate transport and mitochondrial function in synaptosomes.

    PubMed

    Keller, J N; Mark, R J; Bruce, A J; Blanc, E; Rothstein, J D; Uchida, K; Waeg, G; Mattson, M P

    1997-10-01

    Removal of extracellular glutamate at synapses, by specific high-affinity glutamate transporters, is critical to prevent excitotoxic injury to neurons. Oxidative stress has been implicated in the pathogenesis of an array of prominent neurodegenerative conditions that involve degeneration of synapses and neurons in glutamatergic pathways including stroke, and Alzheimer's, Parkinson's and Huntington's diseases. Although cell culture data indicate that oxidative insults can impair key membrane regulatory systems including ion-motive ATPases and amino acid transport systems, the effects of oxidative stress on synapses, and the mechanisms that mediate such effects, are largely unknown. This study provides evidence that 4-hydroxynonenal, an aldehydic product of lipid peroxidation, mediates oxidation-induced impairment of glutamate transport and mitochondrial function in synapses. Exposure of rat cortical synaptosomes to 4-hydroxynonenal resulted in concentration- and time-dependent decreases in [3H]glutamate uptake, and mitochondrial function [assessed with the dye 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)]. Other related aldehydes including malondialdehyde and hexanal had little or no effect on glutamate uptake or mitochondrial function. Exposure of synaptosomes to insults known to induce lipid peroxidation (FeSO4 and amyloid beta-peptide) also impaired glutamate uptake and mitochondrial function. The antioxidants propyl gallate and glutathione prevented impairment of glutamate uptake and MTT reduction induced by FeSO4 and amyloid beta-peptide, but not that induced by 4-hydroxynonenal. Western blot analyses using an antibody to 4-hydroxynonenal-conjugated proteins showed that 4-hydroxynonenal bound to multiple cell proteins including GLT-1, a glial glutamate transporter present at high levels in synaptosomes. 4-Hydroxynonenal itself induced lipid peroxidation suggesting that, in addition to binding directly to membrane regulatory proteins, 4

  18. Targeting cancer using cholesterol conjugates

    PubMed Central

    Radwan, Awwad A.; Alanazi, Fares K.

    2013-01-01

    Conjugation of cholesterol moiety to active compounds for either cancer treatment or diagnosis is an attractive approach. Cholesterol derivatives are widely studied as cancer diagnostic agents and as anticancer derivatives either in vitro or in vivo using animal models. In largely growing studies, anticancer agents have been chemically conjugated to cholesterol molecules, to enhance their pharmacokinetic behavior, cellular uptake, target specificity, and safety. To efficiently deliver anticancer agents to the target cells and tissues, many different cholesterol–anticancer conjugates were synthesized and characterized, and their anticancer efficiencies were tested in vitro and in vivo. PMID:24493968

  19. A Novel NADPH-Dependent Aldehyde Reductase Gene from Saccharomyces cerevisiae NRRL Y-12632 Involved in the Detoxification of Aldehyde Inhibitors Derived from Lignocellulosic Biomass Conversion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aldehyde inhibitors such as furfural, 5-hydroxymethylfurfural (HMF), anisaldehyde, benzaldehyde, cinnamaldehyde, and phenylaldehyde are commonly generated during lignocellulosic biomass conversion process for low-cost cellulosic ethanol production that interferes with subsequent microbial growth and...

  20. A specific affinity reagent to distinguish aldehyde dehydrogenases and oxidases. Enzymes catalyzing aldehyde oxidation in an adult moth

    SciTech Connect

    Tasayco, M.L.; Prestwich, G.D. )

    1990-02-25

    Aldehyde dehydrogenase (ALDH) and oxidase (AO) enzymes from the tissue extracts of male and female tobacco budworm moth (Heliothis virescens) were identified after electrophoretic protein separation. AO activity was visualized using formazan- or horseradish peroxidase-mediated staining coupled to the AO-catalyzed oxidation of benzaldehyde. A set of six soluble AO enzymes with isoelectric points from pI 4.6 to 5.3 were detected primarily in the antennal extracts. Partially purified antennal AO enzymes also oxidized both (Z)-9-tetradecenal and (Z)-11-hexadecenal, the two major pheromone components of this moth. ALDH activity was detected using a tritium-labeled affinity reagent based on a known irreversible inhibitor of this enzyme. This labeled vinyl ketone, (3H)(Z)-1,11-hexadecadien-3-one, was synthesized and used to covalently modify the soluble ALDH enzymes from tissue extracts. Molecular subunits of potential ALDH enzymes were visualized in the fluorescence autoradiograms of sodium dodecyl sulfate-polyacrylamide gel electrophoresis-separated proteins of the antenna, head, and leg tissues. Covalent modification of these protein subunits decreased specifically in the presence of excess pheromone aldehyde or benzaldehyde. Labeled vinyl ketones are thus novel tools for the identification of molecular subunits of ALDH enzymes.

  1. Response of transgenic poplar overexpressing cytosolic glutamine synthetase to phosphinothricin.

    PubMed

    Pascual, María Belén; Jing, Zhong Ping; Kirby, Edward G; Cánovas, Francisco M; Gallardo, Fernando

    2008-01-01

    Glutamine synthetase (GS) is the main enzyme involved in ammonia assimilation in plants and is the target of phosphinothricin (PPT), an herbicide commonly used for weed control in agriculture. As a result of the inhibition of GS, PPT also blocks photorespiration, resulting in the depletion of leaf amino acid pools leading to the plant death. Hybrid transgenic poplar (Populus tremula x P. alba INRA clone 7171-B4) overexpressing cytosolic GS is characterized by enhanced vegetative growth [Gallardo, F., Fu, J., Cantón, F.R., García-Gutiérrez, A., Cánovas, F.M., Kirby, E.G., 1999. Expression of a conifer glutamine synthetase gene in transgenic poplar. Planta 210, 19-26; Fu, J., Sampalo, R., Gallardo, F., Cánovas, F.M., Kirby, E.G., 2003. Assembly of a cytosolic pine glutamine synthetase holoenzyme in leaves of transgenic poplar leads to enhanced vegetative growth in young plants. Plant Cell Environ. 26, 411-418; Jing, Z.P., Gallardo, F., Pascual, M.B., Sampalo, R., Romero, J., Torres de Navarra, A., Cánovas, F.M., 2004. Improved growth in a field trial of transgenic hybrid poplar overexpressing glutamine synthetase. New Phytol. 164, 137-145], increased photosynthetic and photorespiratory capacities [El-Khatib, R.T., Hamerlynck, E.P., Gallardo, F., Kirby, E.G., 2004. Transgenic poplar characterized by ectopic expression of a pine cytosolic glutamine synthetase gene exhibits enhanced tolerance to water stress. Tree Physiol. 24, 729-736], enhanced tolerance to water stress (El-Khatib et al., 2004), and enhanced nitrogen use efficiency [Man, H.-M., Boriel, R., El-Khatib, R.T., Kirby, E.G., 2005. Characterization of transgenic poplar with ectopic expression of pine cytosolic glutamine synthetase under conditions of varying nitrogen availability. New Phytol. 167, 31-39]. In vitro plantlets of GS transgenic poplar exhibited enhanced resistance to PPT when compared with non-transgenic controls. After 30 days exposure to PPT at an equivalent dose of 275 g ha(-1), growth

  2. Cytosolic insulin-binding proteins of mouse liver cells.

    PubMed

    Lokhov, Petr G; Moshkovskii, Sergei A; Ipatova, Olga M; Prozorovskii, Vladimir N

    2004-02-01

    It has been recently shown that insulin retains its biological activity after receptor-directed internalization and it may affect the cell metabolism by interaction with cytosolic insulin-binding proteins (CIBPs). Using affinity chromatography combined with SDS-PAGE and MALDI-TOF mass-spectrometry we have identified 7 proteins from mouse liver cells that specifically bind to the insulin, including adenylate kinase 2 (25.6 kD), kinesin superfamily protein 20B (26.0 kD), hepatic arginase 1 (34.8 kD), fructose-bisphosphate aldolase B (39.5 kD), 4-hydroxyphenylpyruvate dioxygenase (45.1 kD), betaine-homocysteine methyl-transferase (45.0 kD) and KRIT1 (83.4 kD).

  3. Nod-Like Receptors: Cytosolic Watchdogs for Immunity against Pathogens

    PubMed Central

    Sirard, Jean-Claude; Vignal, Cécile; Dessein, Rodrigue; Chamaillard, Mathias

    2007-01-01

    In mammals, tissue-specific sets of pattern-recognition molecules, including Nod-like receptors (NLR), enable concomitant and sequential detection of microbial-associated molecular patterns from both the extracellular and intracellular microenvironment. Repressing and de-repressing the cytosolic surveillance machinery contributes to vital immune homeostasis and protective responses within specific tissues. Conversely, defective biology of NLR drives the development of recurrent infectious, autoimmune and/or inflammatory diseases by failing to mount barrier functions against pathogens, to tolerate commensals, and/or to instruct the adaptive immune response against microbes. Better decoding microbial strategies that are evolved to circumvent NLR sensing will provide clues for the development of rational therapies aimed at curing and/or preventing common and emerging immunopathologies. PMID:18166077

  4. Structural characterization of coatomer in its cytosolic state.

    PubMed

    Wang, Shengliu; Zhai, Yujia; Pang, Xiaoyun; Niu, Tongxin; Ding, Yue-He; Dong, Meng-Qiu; Hsu, Victor W; Sun, Zhe; Sun, Fei

    2016-08-01

    Studies on coat protein I (COPI) have contributed to a basic understanding of how coat proteins generate vesicles to initiate intracellular transport. The core component of the COPI complex is coatomer, which is a multimeric complex that needs to be recruited from the cytosol to membrane in order to function in membrane bending and cargo sorting. Previous structural studies on the clathrin adaptors have found that membrane recruitment induces a large conformational change in promoting their role in cargo sorting. Here, pursuing negative-stain electron microscopy coupled with single-particle analyses, and also performing CXMS (chemical cross-linking coupled with mass spectrometry) for validation, we have reconstructed the structure of coatomer in its soluble form. When compared to the previously elucidated structure of coatomer in its membrane-bound form we do not observe a large conformational change. Thus, the result uncovers a key difference between how COPI versus clathrin coats are regulated by membrane recruitment. PMID:27472951

  5. Acyclovir-induced nephrotoxicity: the role of the acyclovir aldehyde metabolite.

    PubMed

    Gunness, Patrina; Aleksa, Katarina; Bend, John; Koren, Gideon

    2011-11-01

    For decades, acyclovir-induced nephrotoxicity was believed to be secondary to crystalluria. Clinical evidence of nephrotoxicity in the absence of crystalluria suggests that acyclovir induces direct insult to renal tubular cells. We postulated that acyclovir is metabolized by the alcohol dehydrogenase (ADH) enzyme to acyclovir aldehyde, which is metabolized by the aldehyde dehydrognase 2 (ALDH2) enzyme to 9-carboxymethoxymethylguanine (CMMG). We hypothesized that acyclovir aldehyde plays a role in acyclovir-induced nephrotoxicity. Human renal proximal tubular (HK-2) cells were used as our in vitro model. Western blot and enzymes activities assays were performed to determine whether the HK-2 cells express ADH and ALDH2 isozymes, respectively. Cytotoxicity (measured as a function of cell viability) assays were conducted to determine (1) whether the acyclovir aldehyde plays a role in acyclovir-induced nephrotoxicity and (2) whether CMMG induces cell death. A colorimetric assay was performed to determine whether acyclovir was metabolized to an aldehyde in vitro. Our results illustrated that (1) HK-2 cells express ADH and ALDH2 isozymes, (2) 4-methylpyrazole rendered significant protection against cell death, (3) CMMG does not induce cell death, and (4) acyclovir was metabolized to an aldehyde in tubular cells. These data indicate that acyclovir aldehyde is produced in HK-2 cells and that inhibition of its production by 4-methylpyrazole offers significant protection from cell death in vitro, suggesting that acyclovir aldehyde may cause the direct renal tubular insult associated with acyclovir.

  6. Metal-Free Direct Oxidation of Aldehydes to Esters Using TCCA.

    PubMed

    Gaspa, Silvia; Porcheddu, Andrea; De Luca, Lidia

    2015-08-01

    Aromatic and aliphatic aldehydes are simply converted into esters by an efficient oxidative esterification carried out under mild conditions. The aldehydes are converted in situ into their corresponding acyl chlorides, which are then reacted with primary and secondary aliphatic, benzylic, allylic, and propargylic alcohols and phenols. A variety of esters are obtained in high yields.

  7. Threshold responses in cinnamic-aldehyde-sensitive subjects: results and methodological aspects.

    PubMed

    Johansen, J D; Andersen, K E; Rastogi, S C; Menne, T

    1996-03-01

    Cinnamic aldehyde is an important fragrance material and contact allergen. The present study was performed to provide quantitative data on the eliciting capacity of cinnamic aldehyde, to be considered in assessment of clinical relevance and health hazard. The skin response to serial dilution patch tests and 6-week graded use tests with 0.02, 0.1 and 0.8% cinnamic aldehyde in ethanol was studied in a group of cinnamic-aldehyde-sensitive eczema patients. The minimum effect level demonstrated was 0.02% cinnamic aldehyde on patch testing and 0.1% cinnamic aldehyde on use testing, which are allowed usage concentrations in different kind of cosmetics. 72% (13/18) developed eczema in the use test performed with an alcoholic solution of cinnamic aldehyde on healthy upper arm skin. 6 of the 13 use-test-positive subjects (46%) reacted later than day 7, indicating that the standard exposure period of 7 days in use testing may not be sufficient, if low concentrations or volatile substances are used. A significant correlation between patch test sensitivity and the outcome of use testing was found (1,<0.001), which should be considered in designing future use test studies and advising patients. Detailed exposure information is needed to evaluate more fully the consequences of cinnamic aldehyde sensitivity.

  8. Draft Genome Sequence of Aldehyde-Degrading Strain Halomonas axialensis ACH-L-8

    PubMed Central

    Ye, Jun; Ren, Chong; Shan, Xiexie

    2016-01-01

    Halomonas axialensis ACH-L-8, a deep-sea strain isolated from the South China Sea, has the ability to degrade aldehydes. Here, we present an annotated draft genome sequence of this species, which could provide fundamental molecular information on the aldehydes-degrading mechanism. PMID:27081145

  9. Catalytic Fehling's Reaction: An Efficient Aerobic Oxidation of Aldehyde Catalyzed by Copper in Water.

    PubMed

    Liu, Mingxin; Li, Chao-Jun

    2016-08-26

    The first example of homogeneous copper-catalyzed aerobic oxidation of aldehydes is reported. This method utilizes atmospheric oxygen as the sole oxidant, proceeds under extremely mild aqueous conditions, and covers a wide range of various functionalized aldehydes. Chromatography is generally not necessary for product purification. PMID:27505714

  10. Cu-NHC-TEMPO catalyzed aerobic oxidation of primary alcohols to aldehydes.

    PubMed

    Liu, Xiaolong; Xia, Qinqin; Zhang, Yuejiao; Chen, Congyan; Chen, Wanzhi

    2013-09-01

    Imidazolium salts bearing TEMPO groups react with commercially available copper powder affording Cu-NHC complexes. The in situ generated Cu-NHC-TEMPO complexes are quite efficient catalysts for aerobic oxidation of primary alcohols into aldehydes. The catalyst is easily available, and various primary alcohols were selectively converted to aldehydes in excellent yields. PMID:23944937

  11. Draft Genome Sequence of Aldehyde-Degrading Strain Halomonas axialensis ACH-L-8.

    PubMed

    Ye, Jun; Ren, Chong; Shan, Xiexie; Zeng, Runying

    2016-01-01

    Halomonas axialensisACH-L-8, a deep-sea strain isolated from the South China Sea, has the ability to degrade aldehydes. Here, we present an annotated draft genome sequence of this species, which could provide fundamental molecular information on the aldehydes-degrading mechanism.

  12. Regulation of expression of the rodent cytosolic sulfotransferases.

    PubMed

    Runge-Morris, M A

    1997-02-01

    Understanding the molecular regulation of the sulfotransferases is important because these enzymes are essential to a number of critical biological processes. Sulfotransferase expression clearly plays a role in xenobiotic detoxication, carcinogen activation, prodrug processing, cellular signaling pathways, and the regulation of intratissue active androgen and estrogen levels. Although cytosolic sulfotransferases are present in the gut, adrenal, kidney, lung, skin, brain, and other extrahepatic tissues, the basis for the molecular regulation of this complicated gene family has been best characterized in the rat liver, where sulfotransferase levels are relatively abundant. Advances in genomic cloning and in the molecular characterization of individual sulfotransferase cDNAs have inspired new insights into the mechanisms involved in sulfotransferase gene regulation. In particular, the hypothalamic-pituitary-gonadal-adrenocortical axis appears to play a significant role in the regulation of individual sulfotransferase genes. The molecular signals that fluctuate with developmental age, gender, and the occurrence of systemic endocrinopathies also influence sulfotransferase gene expression. For example, diabetes, which disrupts glucose and ketone homeostasis, insulin sensitivity, gonadal and neuroendocrine hormone balance, protein kinase C isoform expression, and P450 metabolism, also disturbs hepatic sulfotransferase gene expression. What role does sulfotransferase expression play in target organ toxicity? Do xenobiotic-mediated changes in sulfotransferase expression compromise detoxication? Does deregulated sulfotransferase expression during development lead to birth defects by perturbing the delicate balance of active hormone levels in fetal tissues? Do conditions of glucocorticoid excess, such as stress or high-dose glucocorticoid therapy induce sulfotransferase expression and place toxicant and carcinogen bioactivation systems in overdrive? This review will summarize

  13. Inhibiting cytosolic translation and autophagy improves health in mitochondrial disease

    PubMed Central

    Peng, Min; Ostrovsky, Julian; Kwon, Young Joon; Polyak, Erzsebet; Licata, Joseph; Tsukikawa, Mai; Marty, Eric; Thomas, Jeffrey; Felix, Carolyn A.; Xiao, Rui; Zhang, Zhe; Gasser, David L.; Argon, Yair; Falk, Marni J.

    2015-01-01

    Mitochondrial respiratory chain (RC) disease therapies directed at intra-mitochondrial pathology are largely ineffective. Recognizing that RC dysfunction invokes pronounced extra-mitochondrial transcriptional adaptations, particularly involving dysregulated translation, we hypothesized that translational dysregulation is itself contributing to the pathophysiology of RC disease. Here, we investigated the activities, and effects from direct inhibition, of a central translational regulator (mTORC1) and its downstream biological processes in diverse genetic and pharmacological models of RC disease. Our data identify novel mechanisms underlying the cellular pathogenesis of RC dysfunction, including the combined induction of proteotoxic stress, the ER stress response and autophagy. mTORC1 inhibition with rapamycin partially ameliorated renal disease in B6.Pdss2kd/kd mice with complexes I–III/II–III deficiencies, improved viability and mitochondrial physiology in gas-1(fc21) nematodes with complex I deficiency, and rescued viability across a variety of RC-inhibited human cells. Even more effective was probucol, a PPAR-activating anti-lipid drug that we show also inhibits mTORC1. However, directly inhibiting mTORC1-regulated downstream activities yielded the most pronounced and sustained benefit. Partial inhibition of translation by cycloheximide, or of autophagy by lithium chloride, rescued viability, preserved cellular respiratory capacity and induced mitochondrial translation and biogenesis. Cycloheximide also ameliorated proteotoxic stress via a uniquely selective reduction of cytosolic protein translation. RNAseq-based transcriptome profiling of treatment effects in gas-1(fc21) mutants provide further evidence that these therapies effectively restored altered translation and autophagy pathways toward that of wild-type animals. Overall, partially inhibiting cytosolic translation and autophagy offer novel treatment strategies to improve health across the diverse

  14. Intracellular Delivery System for Antibody–Peptide Drug Conjugates

    PubMed Central

    Berguig, Geoffrey Y; Convertine, Anthony J; Frayo, Shani; Kern, Hanna B; Procko, Erik; Roy, Debashish; Srinivasan, Selvi; Margineantu, Daciana H; Booth, Garrett; Palanca-Wessels, Maria Corinna; Baker, David; Hockenbery, David; Press, Oliver W; Stayton, Patrick S

    2015-01-01

    Antibodies armed with biologic drugs could greatly expand the therapeutic potential of antibody–drug conjugates for cancer therapy, broadening their application to disease targets currently limited by intracellular delivery barriers. Additional selectivity and new therapeutic approaches could be realized with intracellular protein drugs that more specifically target dysregulated pathways in hematologic cancers and other malignancies. A multifunctional polymeric delivery system for enhanced cytosolic delivery of protein drugs has been developed that incorporates endosomal-releasing activity, antibody targeting, and a biocompatible long-chain ethylene glycol component for optimized safety, pharmacokinetics, and tumor biodistribution. The pH-responsive polymeric micelle carrier, with an internalizing anti-CD22 monoclonal targeting antibody, effectively delivered a proapoptotic Bcl-2 interacting mediator (BIM) peptide drug that suppressed tumor growth for the duration of treatment and prolonged survival in a xenograft mouse model of human B-cell lymphoma. Antitumor drug activity was correlated with a mechanistic induction of the Bcl-2 pathway biomarker cleaved caspase-3 and a marked decrease in the Ki-67 proliferation biomarker. Broadening the intracellular target space by more effective delivery of protein/peptide drugs could expand the repertoire of antibody–drug conjugates to currently undruggable disease-specific targets and permit tailored drug strategies to stratified subpopulations and personalized medicines. PMID:25669432

  15. Metallocene-containing conjugated polymers.

    PubMed

    Vorotyntsev, Mikhail A; Vasilyeva, Svetlana V

    2008-06-22

    The paper gives a review of publications on polymers with conjugated matrices (PPy, PTh, PAni, hydrocarbon or mixed chains...) which incorporate metallocene complexes (Fe, Ru, Co; Ni, Ti, Zr, Ta) with two cyclopentadienyl ligands (Cp) and their derivatives, in particular with methylated cyclopentadienyl rings (Cp*), as well as hemi-metallocene complexes (Fe, Ru, Co, Mn), as pendant groups or inside the principal chain (part B). The information on related short-chain systems, monomers and oligomers, is also included. In part A, a brief overview of various conjugated polymer materials is presented, with their classification in accordance with the conductivity mechanism (ionic, electronic or mixed conductors) or with the structural type (linear-chain organic or mixed polymers, derivatization, metallopolymers, multi-dimensional structures, alternating and block copolymers with organic or mixed units, hybrid materials with a mixture of conjugated and inert polymers, polymers inside a solid matrix, conjugated polymers with incorporated nanoelements of transition metals, carbon, semiconductors etc.

  16. Concerted actions of the catechol O-methyltransferase and the cytosolic sulfotransferase SULT1A3 in the metabolism of catecholic drugs.

    PubMed

    Kurogi, Katsuhisa; Alazizi, Adnan; Liu, Ming-Yih; Sakakibara, Yoichi; Suiko, Masahito; Sugahara, Takuya; Liu, Ming-Cheh

    2012-11-01

    Catecholic drugs had been reported to be metabolized through conjugation reactions, particularly methylation and sulfation. Whether and how these two Phase II conjugation reactions may occur in a concerted manner, however, remained unclear. The current study was designed to investigate the methylation and/or sulfation of five catecholic drugs. Analysis of the spent media of HepG2 cells metabolically labeled with [(35)S]sulfate in the presence of individual catecholic drugs revealed the presence of two [(35)S]sulfated metabolites for dopamine, epinephrine, isoproterenol, and isoetharine, but only one [(35)S]sulfated metabolite for apomorphine. Further analyses using tropolone, a catechol O-methyltransferase (COMT) inhibitor, indicated that one of the two [(35)S]sulfated metabolites of dopamine, epinephrine, isoproterenol, and isoetharine was a doubly conjugated (methylated and sulfated) product, since its level decreased proportionately with increasing concentrations of tropolone added to the labeling media. Moreover, while the inhibition of methylation resulted in a decrease of the total amount of [(35)S]sulfated metabolites, sulfation appeared to be capable of compensating the suppressed methylation in the metabolism of these four catecholic drugs. A two-stage enzymatic assay showed the sequential methylation and sulfation of dopamine, epinephrine, isoproterenol, and isoetharine mediated by, respectively, the COMT and the cytosolic sulfotransferase SULT1A3. Collectively, the results from the present study implied the concerted actions of the COMT and SULT1A3 in the metabolism of catecholic drugs.

  17. Chromatographic approaches for determination of low-molecular mass aldehydes in bio-oil.

    PubMed

    Tessini, Catherine; Müller, Niels; Mardones, Claudia; Meier, Dietrich; Berg, Alex; von Baer, Dietrich

    2012-01-01

    HPLC-UV and GC/MS determination of aldehydes in bio-oil were evaluated. HPLC-UV preceded by derivatization with 2,4-dinitrophenylhydrazine allows separation and detection of bio-oil aldehydes, but the derivatization affected the bio-oil stability reducing their quantitative applicability. GC/MS determination of aldehydes was reached by derivatization with o-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine hydrochloride. Two approaches for this reaction were evaluated. The first: "in solution derivatization and head space extraction" and the second: "on fiber derivatization SPME", the latter through an automatic procedure. Both sample treatments allows the quantification of most important aliphatic aldehydes in bio-oil, being the SPME approach more efficient. The aldehyde concentrations in bio-oil were ~2% formaldehyde, ~!0.1% acetaldehyde and ~0.05% propionaldehyde.

  18. Synthesis of bio-based aldehyde from seaweed polysaccharide and its interaction with bovine serum albumin.

    PubMed

    Kholiya, Faisal; Chaudhary, Jai Prakash; Vadodariya, Nilesh; Meena, Ramavatar

    2016-10-01

    Here, we demonstrate a successful synthesis of bio-based aldehyde namely dialdehyde-carboxymethylagarose (DCMA) using carboxymethyagarose (CMA). Further reaction parameters (i.e. reaction temperature, pH and periodate concentration) were optimized to achieve maximum aldehyde content and product yield. The synthesis of DCMA was confirmed by employing FTIR, (1)H NMR, XRD, SEM, AFM, TGA, DSC, EA and GPC techniques. To investigate the aldehyde functionality, DCMA was allowed to interact with BSA and obtained results were found to be comparable with that of synthetic aldehyde (Formaldehyde). Further interaction of DCMA with BSA was confirmed by using UV-vis, FTIR, fluorescent spectroscopy, CD and DLS analysis. Results of this study revealed that bio-based aldehyde behaves like formaldehyde. This study adds value to abundant marine biopolymers and opens the new research area for polymer researchers. PMID:27312639

  19. Aldehyde dehydrogenases: From eye crystallins to metabolic disease and cancer stem cells

    PubMed Central

    Vasiliou, Vasilis; Thompson, David C.; Smith, Clay; Fujita, Mayumi; Chen, Ying

    2014-01-01

    The aldehyde dehydrogenase (ALDH) superfamily is composed of nicotinamide adenine dinucleotide (phosphate) (NAD(P)+)-dependent enzymes that catalyze the oxidation of aldehydes to their corresponding carboxylic acids. To date, 24 ALDH gene families have been identified in the eukaryotic genome. In addition to aldehyde metabolizing capacity, ALDHs have additional catalytic (e.g. esterase and reductase) and non-catalytic activities. The latter include functioning as structural elements in the eye (crystallins) and as binding molecules to endobiotics and xenobiotics. Mutations in human ALDH genes and subsequent inborn errors in aldehyde metabolism are the molecular basis of several diseases. Most recently ALDH polymorphisms have been associated with gout and osteoporosis. Aldehyde dehydrogenase enzymes also play important roles in embryogenesis and development, neurotransmission, oxidative stress and cancer. This article serves as a comprehensive review of the current state of knowledge regarding the ALDH superfamily and the contribution of ALDHs to various physiological and pathophysiological processes. PMID:23159885

  20. [Characterization of aldehyde dehydrogenase gene fragment from mung bean Vigna radiata using the polymerase chain reaction].

    PubMed

    Ponomarev, A G; Bubiakina, V V; Tatarinova, T D; Zelenin, S M

    1998-01-01

    Two degenerate oligonucleotide sequence primers and polymerase chain reactions on total DNA have been utilized to clone on 651--bp gene fragment coding the central part of amino acid sequence of an earlier unknown aldehyde dehydrogenase (ALDH) from mung bean. The deduced partial amino acid sequence for this aldehyde dehydrogenase shows about 65% sequence identity to ALDHs of Vibrio cholerae Rhodococcus sp., Alcaligenes eutrophus and about 45% sequence identity to mammalian ALDHs 1 and 2, ALDHs of Aspergillus niger and A, nidulans, the betain aldehyde dehydrogenase from spinach. Alignment of the mung bean aldehyde dehydrogenase partial amino acid sequence with the sequence of 16 NAD(P)(+)-dependent aldehyde dehydrogenases has demonstrated that all strictly conserved amino acid residues and all three conservative regions are identical. PMID:9778740

  1. Spacecraft Maximum Allowable Concentrations (SMACs) for C3 to C8 Aliphatic Saturated Aldehydes

    NASA Technical Reports Server (NTRS)

    Langford, Shannon D.

    2007-01-01

    Spacecraft maximum allowable concentrations (SMACs) for C3 to C8, straight-chain, aliphatic aldehydes have been previously assessed and have been documented in volume 4 of Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants (James, 2000). These aldehydes as well as associated physical properties are shown in Table 1. The C3 to C8 aliphatic aldehydes can enter the habitable compartments and contaminate breathing air of spacecraft by several routes including incomplete oxidation of alcohols in the Environmental Control and Life Support System (ECLSS) air revitalization subsystem, as a byproduct of human metabolism, through materials off-gassing, or during food preparation. These aldehydes have been detected in the atmosphere of manned space vehicles in the past. Analysis performed by NASA of crew cabin air samples from the Russian Mir Space Station revealed the presence of C3 to C8 aldehydes at concentrations peaking at approximately 0.1 mg/cu m.

  2. Fatty Aldehydes in Cyanobacteria Are a Metabolically Flexible Precursor for a Diversity of Biofuel Products

    PubMed Central

    Kaiser, Brett K.; Carleton, Michael; Hickman, Jason W.; Miller, Cameron; Lawson, David; Budde, Mark; Warrener, Paul; Paredes, Angel; Mullapudi, Srinivas; Navarro, Patricia; Cross, Fred; Roberts, James M.

    2013-01-01

    We describe how pathway engineering can be used to convert a single intermediate derived from lipid biosynthesis, fatty aldehydes, into a variety of biofuel precursors including alkanes, free fatty acids and wax esters. In cyanobacteria, long-chain acyl-ACPs can be reduced to fatty aldehydes, and then decarbonylated to alkanes. We discovered a cyanobacteria class-3 aldehyde-dehydrogenase, AldE, that was necessary and sufficient to instead oxidize fatty aldehyde precursors into fatty acids. Overexpression of enzymes in this pathway resulted in production of 50 to 100 fold more fatty acids than alkanes, and the fatty acids were secreted from the cell. Co-expression of acyl-ACP reductase, an alcohol-dehydrogenase and a wax-ester-synthase resulted in a third fate for fatty aldehydes: conversion to wax esters, which accumulated as intracellular lipid bodies. Conversion of acyl-ACP to fatty acids using endogenous cyanobacterial enzymes may allow biofuel production without transgenesis. PMID:23505484

  3. Design, synthesis, and immunologic evaluation of vaccine adjuvant conjugates based on QS-21 and tucaresol.

    PubMed

    Fernández-Tejada, Alberto; Chea, Eric K; George, Constantine; Gardner, Jeffrey R; Livingston, Philip O; Ragupathi, Govind; Tan, Derek S; Gin, David Y

    2014-11-01

    Immunoadjuvants are used to potentiate the activity of modern subunit vaccines that are based on molecular antigens. An emerging approach involves the combination of multiple adjuvants in a single formulation to achieve optimal vaccine efficacy. Herein, to investigate such potential synergies, we synthesized novel adjuvant conjugates based on the saponin natural product QS-21 and the aldehyde tucaresol via chemoselective acylation of an amine at the terminus of the acyl chain domain in QS saponin variants. In a preclinical mouse vaccination model, these QS saponin-tucaresol conjugates induced antibody responses similar to or slightly higher than those generated with related QS saponin variants lacking the tucaresol motif. The conjugates retained potent adjuvant activity, low toxicity, and improved activity-toxicity profiles relative to QS-21 itself and induced IgG subclass profiles similar to those of QS-21, indicative of both Th1 cellular and Th2 humoral immune responses. This study opens the door to installation of other substituents at the terminus of the acyl chain domain to develop additional QS saponin conjugates with desirable immunologic properties.

  4. Polymeric conjugates for drug delivery

    PubMed Central

    Larson, Nate; Ghandehari, Hamidreza

    2012-01-01

    The field of polymer therapeutics has evolved over the past decade and has resulted in the development of polymer-drug conjugates with a wide variety of architectures and chemical properties. Whereas traditional non-degradable polymeric carriers such as poly(ethylene glycol) (PEG) and N-(2-hydroxypropyl methacrylamide) (HPMA) copolymers have been translated to use in the clinic, functionalized polymer-drug conjugates are increasingly being utilized to obtain biodegradable, stimuli-sensitive, and targeted systems in an attempt to further enhance localized drug delivery and ease of elimination. In addition, the study of conjugates bearing both therapeutic and diagnostic agents has resulted in multifunctional carriers with the potential to both “see and treat” patients. In this paper, the rational design of polymer-drug conjugates will be discussed followed by a review of different classes of conjugates currently under investigation. The design and chemistry used for the synthesis of various conjugates will be presented with additional comments on their potential applications and current developmental status. PMID:22707853

  5. Protein carriers of conjugate vaccines

    PubMed Central

    Pichichero, Michael E

    2013-01-01

    The immunogenicity of polysaccharides as human vaccines was enhanced by coupling to protein carriers. Conjugation transformed the T cell-independent polysaccharide vaccines of the past to T cell-dependent antigenic vaccines that were much more immunogenic and launched a renaissance in vaccinology. This review discusses the conjugate vaccines for prevention of infections caused by Hemophilus influenzae type b, Streptococcus pneumoniae, and Neisseria meningitidis. Specifically, the characteristics of the proteins used in the construction of the vaccines including CRM, tetanus toxoid, diphtheria toxoid, Neisseria meningitidis outer membrane complex, and Hemophilus influenzae protein D are discussed. The studies that established differences among and key features of conjugate vaccines including immunologic memory induction, reduction of nasopharyngeal colonization and herd immunity, and antibody avidity and avidity maturation are presented. Studies of dose, schedule, response to boosters, of single protein carriers with single and multiple polysaccharides, of multiple protein carriers with multiple polysaccharides and conjugate vaccines administered concurrently with other vaccines are discussed along with undesirable consequences of conjugate vaccines. The clear benefits of conjugate vaccines in improving the protective responses of the immature immune systems of young infants and the senescent immune systems of the elderly have been made clear and opened the way to development of additional vaccines using this technology for future vaccine products. PMID:23955057

  6. Characterization of the cytosolic distribution of priority pollutant metals and metalloids in the digestive gland cytosol of marine mussels: seasonal and spatial variability.

    PubMed

    Strižak, Zeljka; Ivanković, Dušica; Pröfrock, Daniel; Helmholz, Heike; Cindrić, Ana-Marija; Erk, Marijana; Prange, Andreas

    2014-02-01

    Cytosolic profiles of several priority pollutant metals (Cu, Cd, Zn, Pb) and metalloid As were analyzed in the digestive gland of the mussel (Mytilus galloprovincialis) sampled at locations with different environmental pollution levels along the Croatian coast in the spring and summer season. Size-exclusion chromatography (SEC) connected to inductively coupled plasma mass spectrometry (ICP-MS) was used to determine selected elements bound to cytosolic biomolecules separated based on their molecular size. Copper, cadmium and zinc eluted mostly associated with high molecular weight (HMW) and medium molecular weight (MMW) biomolecules, but with a more prominent elution in the MMW peak at polluted locations which were probably associated with the 20 kDa metallothionein (MT). Elution of all three metals within this peak was also strongly correlated with cytosolic Cd as strong inducer of MT. Lead mostly eluted in HMW biomolecule range, but in elevated cytosolic Pb concentrations, significant amount eluted in low molecular weight (LMW) biomolecules. Arsenic, on the other hand eluted almost completely in LMW range, but we could not distinguish specific molecular weight biomolecules which would be predominant in detoxification mechanism. Seasonal variability in element abundance within specific peaks was present, although not in the same extent, for all elements and locations, especially for As. The results confirm the suitability of the distribution of selected metals/metalloids among different cytosolic ligands as potential indicator for metal exposure. Obtained findings can also serve as guidelines for further separation and characterization of specific cytosolic metal-binding biomolecules.

  7. Multicomponent reactions of methyl substituted all-cis tetrafluorocyclohexane aldehydes.

    PubMed

    Bykova, Tetiana; Al-Maharik, Nawaf; Slawin, Alexandra M Z; O'Hagan, David

    2016-01-21

    This paper reports the preparation of methyl substituted all-cis tetrafluorocyclohexanes prepared from a Birch reduction of benzoic acid, worked up with a methyl iodide quench. The resultant methylcyclohexadiene carboxylic acid was reduced to the alcohol, protected as an ether and then a sequence of functional group manipulations carried out to introduce four fluorines. The cyclohexadienyl ring was then epoxidised and the C-O bonds sequentially converted through deoxyfluorination reactions to two sets of isomers of all-cis tetrafluorocyclohexane isomers. The blocking methyl group renders the ring safe to hydrogen fluoride elimination. Deprotection of the benzylic ether and then oxidation gave aldehydes which were then used in Ugi and Passerini multicomponent reactions, allowing this facially polarised cyclohexane to be incorporated into peptidic structural motifs. PMID:26646211

  8. Possible prebiotic catalysts formed from adenine and aldehyde

    NASA Astrophysics Data System (ADS)

    Vergne, J.; Dumas, L.; Décout, J.-L.; Maurel, M.-C.

    2000-09-01

    Careful examination of the present metabolism and in vitro selection of various catalytic RNAs strongly support the "RNA World" hypothesis of the origin of life. However, in this scenario, the difficult prebiotic synthesis of ribose and consequently of nucleotides remain a major problem. In order to overcome this problem and obtain nucleoside analogs, we are investigating reactions of the nucleic acid base, adenine 1, with different aldehydes under presumably prebiotic conditions. In the reaction of adenine and pyruvaldehyde 2 in water, we report here the formation in high yield of two isomeric products. These compounds possessing alcohols functions as nucleosides result from condensation of two molecules of pyruvaldehyde on the 6-amino group of one adenine molecule. Their catalytic activities in the model hydrolysis of p-nitrophenylesters appeared interesting in the search of prebiotic catalysts.

  9. Studies on organic indole-3-aldehyde single crystals

    NASA Astrophysics Data System (ADS)

    Haja Hameed, A. S.; Ravi, G.; Dhanasekaran, R.; Ramasamy, P.

    Indole-3-aldehyde (IA) is a new organic nonlinear material for which its solubility in methanol and acetone was found out using the apparatus fabricated by the authors. In order to get the good-quality crystals, methods of evaporation of solvent at room temperature and slow cooling of saturated solution at boiling temperature were adopted. Simulated lattice parameter values were found out using experimentally known " d" values. The etching and mechanical strength studies on different planes of the crystal were carried out. Decomposition temperature, weight loss and different functional bond frequencies associated with the crystal were also found out from differential thermal analysis (DTA), thermo-gravimetric analysis (TGA) and Fourier transform infra-red (FTIR) spectroscopic analysis, respectively.

  10. Pharmacological activities of cilantro's aliphatic aldehydes against Leishmania donovani.

    PubMed

    Donega, Mateus A; Mello, Simone C; Moraes, Rita M; Jain, Surendra K; Tekwani, Babu L; Cantrell, Charles L

    2014-12-01

    Leishmaniasis is a chronic infectious disease caused by different Leishmania species. Global occurrences of this disease are primarily limited to tropical and subtropical regions. Treatments are available; however, patients complain of side effects. Different species of plants have been screened as a potential source of new drugs against leishmaniasis. In this study, we investigated the antileishmanial activity of cilantro (Coriandrum sativum) essential oil and its main components: (E)-2-undecenal, (E)-2-decenal, (E)-2-dodecenal, decanal, dodecanal, and tetradecanal. The essential oil of C. sativum leaves inhibits growth of Leishmani donovani promastigotes in culture with an IC50 of 26.58 ± 6.11 µg/mL. The aliphatic aldehydes (E)-2-decenal (7.85 ± 0.28 µg/mL), (E)-2-undecenal (2.81 ± 0.21 µg/mL), and (E)-2-dodecenal (4.35 ± 0.15 µg/mL), all isolated from C. sativum essential oil, are effective inhibitors of in vitro cultures of L. donovani promastigotes. Aldehydes (E)-2-decenal, (E)-2-undecenal, and (E)-2-dodecenal were also evaluated against axenic amastigotes and IC50 values were determined to be 2.47 ± 0.25 µg/mL, 1.25 ± 0.11 µg/mL, and 4.78 ± 1.12 µg/mL, respectively. (E)-2-Undecenal and (E)-2-dodecenal demonstrated IC50 values of 5.65 ± 0.19 µg/mL and 9.60 ± 0.89 µg/mL, respectively, against macrophage amastigotes. These cilantro compounds showed no cytotoxicity against THP-1 macrophages. PMID:25340465

  11. Aldehyde dehydrogenase activity promotes survival of human muscle precursor cells

    PubMed Central

    Jean, Elise; Laoudj-Chenivesse, Dalila; Notarnicola, Cécile; Rouger, Karl; Serratrice, Nicolas; Bonnieu, Anne; Gay, Stéphanie; Bacou, Francis; Duret, Cédric; Carnac, Gilles

    2011-01-01

    Abstract Aldehyde dehydrogenases (ALDH) are a family of enzymes that efficiently detoxify aldehydic products generated by reactive oxygen species and might therefore participate in cell survival. Because ALDH activity has been used to identify normal and malignant cells with stem cell properties, we asked whether human myogenic precursor cells (myoblasts) could be identified and isolated based on their levels of ALDH activity. Human muscle explant-derived cells were incubated with ALDEFLUOR, a fluorescent substrate for ALDH, and we determined by flow cytometry the level of enzyme activity. We found that ALDH activity positively correlated with the myoblast-CD56+ fraction in those cells, but, we also observed heterogeneity of ALDH activity levels within CD56-purified myoblasts. Using lentiviral mediated expression of shRNA we demonstrated that ALDH activity was associated with expression of Aldh1a1 protein. Surprisingly, ALDH activity and Aldh1a1 expression levels were very low in mouse, rat, rabbit and non-human primate myoblasts. Using different approaches, from pharmacological inhibition of ALDH activity by diethylaminobenzaldehyde, an inhibitor of class I ALDH, to cell fractionation by flow cytometry using the ALDEFLUOR assay, we characterized human myoblasts expressing low or high levels of ALDH. We correlated high ALDH activity ex vivo to resistance to hydrogen peroxide (H2O2)-induced cytotoxic effect and in vivo to improved cell viability when human myoblasts were transplanted into host muscle of immune deficient scid mice. Therefore detection of ALDH activity, as a purification strategy, could allow non-toxic and efficient isolation of a fraction of human myoblasts resistant to cytotoxic damage. PMID:19840193

  12. Current Injection Provokes Rapid Expansion of the Guard Cell Cytosolic Volume and Triggers Ca(2+) Signals.

    PubMed

    Voss, Lena J; Hedrich, Rainer; Roelfsema, M Rob G

    2016-03-01

    High-resolution microscopy opens the door for detailed single-cell studies with fluorescent reporter dyes and proteins. We used a confocal spinning disc microscope to monitor fluorescent dyes and the fluorescent protein Venus in tobacco and Arabidopsis guard cells. Multi-barreled microelectrodes were used to inject dyes and apply voltage pulses, which provoke transient rises in the cytosolic Ca(2+) level. Voltage pulses also caused changes in the distribution of Lucifer Yellow and Venus, which pointed to a reversible increase of guard cell cytosolic volume. The dynamic cytosolic volume changes turned out to be provoked by current injection of ions. A reduction of the clamp current, by blocking K(+) uptake channels with Cs(+), strongly suppressed the cytosolic volume changes. Cs(+) not only inhibited the expansion of the cytosol, but also inhibited hyperpolarization-induced elevations of the cytosolic Ca(2+) concentration. A complete loss of voltage-induced Ca(2+) signals occurred when Ca(2+)-permeable plasma membrane channels were simultaneously blocked with La(3+). This shows that two mechanisms cause hyperpolarization-induced elevation of the cytosolic Ca(2+)-concentration: (i) activation of voltage-dependent Ca(2+)-permeable channels, (ii) osmotically induced expansion of the cytosol, which leads to a release of Ca(2+) from intracellular stores.

  13. Carbohydrate protease conjugates: Stabilized proteases for peptide synthesis

    SciTech Connect

    Wartchow, C.A.; Wang, Peng; Bednarski, M.D.; Callstrom, M.R. |

    1995-12-31

    The synthesis of oligopeptides using stable carbohydrate protease conjugates (CPCs) was examined in acetonitrile solvent systems. CPC[{alpha}-chymotrypsin] was used for the preparation of peptides containing histidine, phenylalanine, tryptophan in the P{sub 1} position in 60-93% yield. The CPC[{alpha}-chymotrypsin]-catalyzed synthesis of octamer Z-Gly-Gly-Phe-Gly-Gly-Phe-Gly-Gly-OEt from Z-Gly-Gly-Phe-Gly-Gly-Phe-OMe was achieved in 71% yield demonstrating that synthesis peptides containing both hydrophylic and hydrophobic amino acids. The P{sub 2} specificity of papain for aromatic residues was utilized for the 2 + 3 coupling of Z-Tyr-Gly-OMe to H{sub 2}N-Gly-Phe-Leu-OH to generate the leucine enkephalin derivative in 79% yield. Although papain is nonspecific for the hydrolysis of N-benzyloxycarbonyl amino acid methyl esters in aqueous solution, the rates of synthesis for these derivitives with nucleophile leucine tert-butyl ester differed by nearly 2 orders of magnitude. CPC[thermolysin] was used to prepare the aspartame precursor Z-Asp-Phe-OMe in 90% yield. The increased stability of CPCs prepared from periodate-modified poly(2-methacryl- amido-2-deoxy-D-glucose), poly(2-methacrylamido-2-deoxy-D-galactose), and poly(5-methacryl-amido-5-deoxy-D-ribose), carbohydrate materials designed to increase the aldehyde concentration in aqueous solution, suggests that the stability of CPCs is directly related to the aldehyde concentration of the carbohydrate material. Periodate oxidation of poly(2-methacrylamido-2-deoxy-D-glucose) followed by covalent attachment to {alpha}-chymotrypsin gave a CPC with catalytic activity in potassium phosphate buffer at 90{degrees}C for 2 h. 1 fig., 1 tab., 40 refs.

  14. Cationic DOPC-Detergent Conjugates for Safe and Efficient in Vitro and in Vivo Nucleic Acid Delivery.

    PubMed

    Pierrat, Philippe; Casset, Anne; Didier, Pascal; Kereselidze, Dimitri; Lux, Marie; Pons, Françoise; Lebeau, Luc

    2016-09-15

    The ability of a nonviral nucleic acid carrier to deliver its cargo to cells with low associated toxicity is a critical issue for clinical applications of gene therapy. We describe biodegradable cationic DOPC-C12 E4 conjugates in which transfection efficiency is based on a Trojan horse strategy. In situ production of the detergent compound C12 E4 through conjugate hydrolysis within the acidic endosome compartment was expected to promote endosome membrane destabilization and subsequent release of the lipoplexes into cytosol. The transfection efficiency of the conjugates has been assessed in vitro, and associated cytotoxicity was determined. Cellular uptake and intracellular distribution of the lipoplexes have been investigated. The results show that direct conjugation of DOPC with C12 E4 produces a versatile carrier that can deliver both DNA and siRNA to cells in vitro with high efficiency and low cytotoxicity. SAR studies suggest that this compound might represent a reasonable compromise between the membrane activity of the released detergent and susceptibility of the conjugate to degradation enzymes in vitro. Although biodegradability of the conjugates had low impact on carrier efficiency in vitro, it proved critical in vivo. Significant improvement of transgene expression was obtained in the mouse lung tuning biodegradability of the carrier. Importantly, this also allowed reduction of the inflammatory response that invariably characterizes cationic-lipid-mediated gene transfer in animals. PMID:27380144

  15. Cationic DOPC-Detergent Conjugates for Safe and Efficient in Vitro and in Vivo Nucleic Acid Delivery.

    PubMed

    Pierrat, Philippe; Casset, Anne; Didier, Pascal; Kereselidze, Dimitri; Lux, Marie; Pons, Françoise; Lebeau, Luc

    2016-09-15

    The ability of a nonviral nucleic acid carrier to deliver its cargo to cells with low associated toxicity is a critical issue for clinical applications of gene therapy. We describe biodegradable cationic DOPC-C12 E4 conjugates in which transfection efficiency is based on a Trojan horse strategy. In situ production of the detergent compound C12 E4 through conjugate hydrolysis within the acidic endosome compartment was expected to promote endosome membrane destabilization and subsequent release of the lipoplexes into cytosol. The transfection efficiency of the conjugates has been assessed in vitro, and associated cytotoxicity was determined. Cellular uptake and intracellular distribution of the lipoplexes have been investigated. The results show that direct conjugation of DOPC with C12 E4 produces a versatile carrier that can deliver both DNA and siRNA to cells in vitro with high efficiency and low cytotoxicity. SAR studies suggest that this compound might represent a reasonable compromise between the membrane activity of the released detergent and susceptibility of the conjugate to degradation enzymes in vitro. Although biodegradability of the conjugates had low impact on carrier efficiency in vitro, it proved critical in vivo. Significant improvement of transgene expression was obtained in the mouse lung tuning biodegradability of the carrier. Importantly, this also allowed reduction of the inflammatory response that invariably characterizes cationic-lipid-mediated gene transfer in animals.

  16. [Effects of panthenol and carnitine on aldehyde metabolic enzymes in rats with tetrachloromethane-induced liver injury].

    PubMed

    Satanovskaia, V I; Pron'ko, P S; Gaĭshmanova, A V; Miskevich, D A

    2009-01-01

    Tetrachloromethane (2 g/kg, intragastric) produced a decrease in the activity of NAD- and NADH- dependent aldehyde dehydrogenases with high Km for aldehydes in rat liver. Panthenol and L-carnitine administered separately normalized the activity of aldehyde dehydrogenases, while a combination of the drugs did not produce any significant effect. PMID:19441727

  17. Multiple retinoid dehydrogenases in testes cytosol from alcohol dehydrogenase negative or positive deermice.

    PubMed

    Posch, K C; Napoli, J L

    1992-05-28

    Retinoic acid syntheses from retinol by cytosol from testes of alcohol dehydrogenase negative or positive deermice were similar in specific activity and in their insensitivity to 1 M ethanol or 100 mM 4-methylpyrazole. Anion-exchange followed by size-exclusion chromatography revealed multiple and similarly migrating peaks in each cytosol that had both retinol and retinal dehydrogenase activities. Thus, the effects of ethanol on testes cannot be caused by direct inhibition of cytosolic retinoic acid synthesis because retinoid dehydrogenases distinct from mouse class A2 alcohol dehydrogenases, which corresponds to human class I, occurred in testes and they were not inhibited by ethanol. These data also demonstrate the occurrence of multiple cytosolic retinoic acid synthesis activities and indicate that the two reactions of cytosolic retinoic acid synthesis, retinol and retinal dehydrogenation, may be catalyzed by enzymes that occur as complexes. PMID:1599517

  18. Cells die with increased cytosolic ATP during apoptosis: a bioluminescence study with intracellular luciferase.

    PubMed

    Zamaraeva, M V; Sabirov, R Z; Maeno, E; Ando-Akatsuka, Y; Bessonova, S V; Okada, Y

    2005-11-01

    Apoptosis is a distinct form of cell death, which requires energy. Here, we made real-time continuous measurements of the cytosolic ATP level throughout the apoptotic process in intact HeLa, PC12 and U937 cells transfected with the firefly luciferase gene. Apoptotic stimuli (staurosporine (STS), tumor necrosis factor alpha (TNFalpha), etoposide) induced significant elevation of the cytosolic ATP level. The cytosolic ATP level remained at a higher level than in the control for up to 6 h during which activation of caspase-3 and internucleosomal DNA fragmentation took place. When the STS-induced ATP response was abolished by glucose deprivation-induced inhibition of glycolysis, both caspase activation and DNA laddering were completely inhibited. Annexin V-binding induced by STS or TNFalpha was largely suppressed by glycolysis inhibition. Thus, it is suggested that the cells die with increased cytosolic ATP, and elevation of cytosolic ATP level is a requisite to the apoptotic cell death process.

  19. A role for 4-hydroxynonenal, an aldehydic product of lipid peroxidation, in disruption of ion homeostasis and neuronal death induced by amyloid beta-peptide.

    PubMed

    Mark, R J; Lovell, M A; Markesbery, W R; Uchida, K; Mattson, M P

    1997-01-01

    Peroxidation of membrane lipids results in release of the aldehyde 4-hydroxynonenal (HNE), which is known to conjugate to specific amino acids of proteins and may alter their function. Because accumulating data indicate that free radicals mediate injury and death of neurons in Alzheimer's disease (AD) and because amyloid beta-peptide (A beta) can promote free radical production, we tested the hypothesis that HNE mediates A beta 25-35-induced disruption of neuronal ion homeostasis and cell death. A beta induced large increases in levels of free and protein-bound HNE in cultured hippocampal cells. HNE was neurotoxic in a time- and concentration-dependent manner, and this toxicity was specific in that other aldehydic lipid peroxidation products were not neurotoxic. HNE impaired Na+, K(+)-ATPase activity and induced an increase of neuronal intracellular free Ca2+ concentration. HNE increased neuronal vulnerability to glutamate toxicity, and HNE toxicity was partially attenuated by NMDA receptor antagonists, suggesting an excitotoxic component to HNE neurotoxicity. Glutathione, which was previously shown to play a key role in HNE metabolism in nonneuronal cells, attenuated the neurotoxicities of both A beta and HNE. The antioxidant propyl gallate protected neurons against A beta toxicity but was less effective in protecting against HNE toxicity. Collectively, the data suggest that HNE mediates A beta-induced oxidative damage to neuronal membrane proteins, which, in turn, leads to disruption of ion homeostasis and cell degeneration. PMID:8978733

  20. 4-Hydroxynonenal, an aldehydic product of lipid peroxidation, impairs signal transduction associated with muscarinic acetylcholine and metabotropic glutamate receptors: possible action on G alpha(q/11).

    PubMed

    Blanc, E M; Kelly, J F; Mark, R J; Waeg, G; Mattson, M P

    1997-08-01

    Considerable data indicate that oxidative stress and membrane lipid peroxidation contribute to neuronal degeneration in an array of age-related neurodegenerative disorders. In contrast, the impact of subtoxic levels of membrane lipid peroxidation on neuronal function is largely unknown. We now report that 4-hydroxynonenal (HNE), an aldehydic product of lipid peroxidation, disrupts coupling of muscarinic cholinergic receptors and metabotropic glutamate receptors to phospholipase C-linked GTP-binding proteins in cultured rat cerebrocortical neurons. At subtoxic concentrations, HNE markedly inhibited GTPase activity, inositol phosphate release, and elevation of intracellular calcium levels induced by carbachol (muscarinic agonist) and (RS)-3,5-dihydroxyphenyl glycine (metabotropic glutamate receptor agonist). Maximal impairment of agonist-induced responses occurred within 30 min of exposure to HNE. Other aldehydes, including malondialdehyde, had little effect on agonist-induced responses. Antioxidants that suppress lipid peroxidation did not prevent impairment of agonist-induced responses by HNE, whereas glutathione, which is known to bind and detoxify HNE, did prevent impairment of agonist-induced responses. HNE itself did not induce oxidative stress. Immunoprecipitation-western blot analysis using an antibody to HNE-protein conjugates showed that HNE can bind to G alpha(q/11). HNE also significantly suppressed inositol phosphate release induced by aluminum fluoride. Collectively, our data suggest that HNE plays a role in altering receptor-G protein coupling in neurons under conditions of oxidative stress that may occur both normally, and before cell degeneration and death in pathological settings. PMID:9231714

  1. Measurement of cytosolic Ca2+ in isolated contractile lymphatics.

    PubMed

    Souza-Smith, Flavia M; Kurtz, Kristine M; Breslin, Jerome W

    2011-01-01

    Lymphatic vessels comprise a multifunctional transport system that maintains fluid homeostasis, delivers lipids to the central circulation, and acts as a surveillance system for potentially harmful antigens, optimizing mucosal immunity and adaptive immune responses. Lymph is formed from interstitial fluid that enters blind-ended initial lymphatics, and then is transported against a pressure gradient in larger collecting lymphatics. Each collecting lymphatic is made up of a series of segments called lymphangions, separated by bicuspid valves that prevent backflow. Each lymphangion possesses a contractile cycle that propels lymph against a pressure gradient toward the central circulation. This phasic contractile pattern is analogous to the cardiac cycle, with systolic and diastolic phases, and with a lower contraction frequency. In addition, lymphatic smooth muscle generates tone and displays myogenic constriction and dilation in response to increases and decreases in luminal pressure, respectively. A hybrid of molecular mechanisms that support both the phasic and tonic contractility of lymphatics are thus proposed. Contraction of smooth muscle is generally regulated by the cytosolic Ca(2+) concentration ([Ca(2+)](i)) plus sensitivity to Ca(2+) of the contractile elements in response to changes in the environment surrounding the cell. [Ca(2+)](i) is determined by the combination of the movement of Ca(2+) through plasma membrane ligand or voltage gated Ca(2+) channels and the release and uptake of Ca(2+) from internal stores. Cytosolic Ca(2+) binds to calmodulin and activates enzymes such as myosin light chain (MLC) kinase (MLCK), which in turn phosphorylates MLC leading to actin-myosin-mediated contraction. However, the sensitivity of this pathway to Ca(2+) can be regulated by the MLC phosphatase (MLCP). MLCP activity is regulated by Rho kinase (ROCK) and the myosin phosphatase inhibitor protein CPI-17. Here, we present a method to evaluate changes in [Ca(2+)](i

  2. Fatty aldehyde dehydrogenases in Acinetobacter sp. strain HO1-N: role in hexadecane and hexadecanol metabolism

    SciTech Connect

    Singer, M.E.; Finnerty, W.R.

    1985-12-01

    The role of fatty aldehyde dehydrogenases (FALDHs) in hexadecane and hexadecanol metabolism was studied in Acinetobacter sp. strain HO1-N. Two distinct FALDHs were demonstrated in Acinetobacter sp. strain HO1-N: (i) a membrane-bound, NADP-dependent FALDH activity induced 5-, 15-, and 9 fold by growth on hexadecanol, dodecyl aldehyde, and hexadecane, respectively, and (ii) a constitutive, NAD-dependent, membrane-localized FALDH. Dodecyl aldehyde-negative mutants were isolated and grouped into two phenotypic classes based on growth: class 1 mutants were hexadecane and hexadecanol negative and class 2 mutants were hexadecane and hexadecanol positive. Specific activity of NADP-dependent FALDH in Ald21 (class 1 mutant) was 85% lower than that of wild-type FALDH, while the specific activity of Ald24 (class 2 mutant) was 55% greater than that of wild-type FALDH. Ald21R, a dodecyl aldehyde-positive revertant able to grow on hexadecane, hexadecanol, and dodecyl aldehyde, exhibited a 100% increase in the specific activity of the NADP-dependent FALDH. This study provides genetic and physiological evidence for the role of fatty aldehyde as an essential metabolic intermediate and NADP-dependent FALDH as a key enzyme in the dissimilation of hexadecane, hexadecanol, and dodecyl aldehyde in Acinetobacter sp. strain HO1-N.

  3. Dark Hydrazone Fluorescence Labeling Agents Enable Imaging of Cellular Aldehydic Load.

    PubMed

    Yuen, Lik Hang; Saxena, Nivedita S; Park, Hyun Shin; Weinberg, Kenneth; Kool, Eric T

    2016-08-19

    Aldehydes are key intermediates in many cellular processes, from endogenous metabolic pathways like glycolysis to undesired exogenously induced processes such as lipid peroxidation and DNA interstrand cross-linking. Alkyl aldehydes are well documented to be cytotoxic, affecting the functions of DNA and protein, and their levels are tightly regulated by the oxidative enzyme ALDH2. Mutations in this enzyme are associated with cardiac damage, diseases such as Fanconi anemia (FA), and cancer. Many attempts have been made to identify and quantify the overall level of these alkyl aldehydes inside cells, yet there are few practical methods available to detect and monitor these volatile aldehydes in real time. Here, we describe a multicolor fluorogenic hydrazone transfer ("DarkZone") system to label alkyl aldehydes, yielding up to 30-fold light-up response in vitro. A cell-permeant DarkZone dye design was applied to detect small-molecule aldehydes in the cellular environment. The new dye design also enabled the monitoring of cellular acetaldehyde production from ethanol over time by flow cytometry, demonstrating the utility of the DarkZone dyes for measuring and imaging the aldehydic load related to human disease. PMID:27326450

  4. Fatty Aldehyde and Fatty Alcohol Metabolism: Review and Importance for Epidermal Structure and Function

    PubMed Central

    Rizzo, William B.

    2014-01-01

    Normal fatty aldehyde and alcohol metabolism is essential for epidermal differentiation and function. Long-chain aldehydes are produced by catabolism of several lipids including fatty alcohols, sphingolipids, ether glycerolipids, isoprenoid alcohols and certain aliphatic lipids that undergo α- or ω-oxidation. The fatty aldehyde generated by these pathways is chiefly metabolized to fatty acid by fatty aldehyde dehydrogenase (FALDH, alternately known as ALDH3A2), which also functions to oxidize fatty alcohols as a component of the fatty alcohol:NAD oxidoreductase (FAO) enzyme complex. Genetic deficiency of FALDH/FAO in patients with Sjögren-Larsson syndrome (SLS) results in accumulation of fatty aldehydes, fatty alcohols and related lipids (ether glycerolipids, wax esters) in cultured keratinocytes. These biochemical changes are associated with abnormalities in formation of lamellar bodies in the stratum granulosum and impaired delivery of their precursor membranes to the stratum corneum (SC). The defective extracellular SC membranes are responsible for a leaky epidermal water barrier and ichthyosis. Although lamellar bodies appear to be the pathogenic target for abnormal fatty aldehyde/alcohol metabolism in SLS, the precise biochemical mechanisms are yet to be elucidated. Nevertheless, studies in SLS highlight the critical importance of FALDH and normal fatty aldehyde/alcohol metabolism for epidermal function. PMID:24036493

  5. Cytosolic rat brain synapsin I is a diacylglycerol kinase.

    PubMed Central

    Kahn, D W; Besterman, J M

    1991-01-01

    The phosphorylation of diacylglycerol (DG), a reaction catalyzed by DG kinase, may be critical in the termination of effector-induced signals mediated by protein kinase C. Synapsin I is a principal target of intracellular protein kinases and is thought to be involved in the release of neurotransmitter from axon terminals. We present several lines of evidence which indicate that rat brain synapsin, in addition to this role, may function as a DG kinase. Purified rat brain DG kinase was digested with trypsin, which produced three major fragments whose sequence was identical to three regions in synapsin I. Using a rabbit anti-synapsin polyclonal antiserum, the elution profile of synapsin immunoreactivity coincided exactly with that of DG kinase activity in column fractions from the final step in the DG kinase purification procedure. As is the case with synapsin, the purified enzyme was a strongly basic protein with an isoelectric point greater than 10.0. Finally, incubating the DG kinase with highly purified bacterial collagenase, an enzyme that partially degrades the proline- and glycine-rich synapsin, resulted in the simultaneous loss of DG kinase activity and synapsin immunoreactivity. We conclude that cytosolic rat brain synapsin is capable of functioning as a DG kinase. Images PMID:1648730

  6. Horizontal Transmission of Cytosolic Sup35 Prions by Extracellular Vesicles

    PubMed Central

    Liu, Shu; Hossinger, André; Hofmann, Julia P.; Denner, Philip

    2016-01-01

    ABSTRACT Prions are infectious protein particles that replicate by templating their aggregated state onto soluble protein of the same type. Originally identified as the causative agent of transmissible spongiform encephalopathies, prions in yeast (Saccharomyces cerevisiae) are epigenetic elements of inheritance that induce phenotypic changes of their host cells. The prototype yeast prion is the translation termination factor Sup35. Prions composed of Sup35 or its modular prion domain NM are heritable and are transmitted vertically to progeny or horizontally during mating. Interestingly, in mammalian cells, protein aggregates derived from yeast Sup35 NM behave as true infectious entities that employ dissemination strategies similar to those of mammalian prions. While transmission is most efficient when cells are in direct contact, we demonstrate here that cytosolic Sup35 NM prions are also released into the extracellular space in association with nanometer-sized membrane vesicles. Importantly, extracellular vesicles are biologically active and are taken up by recipient cells, where they induce self-sustained Sup35 NM protein aggregation. Thus, in mammalian cells, extracellular vesicles can serve as dissemination vehicles for protein-based epigenetic information transfer. PMID:27406566

  7. Cytosolic Access of Intracellular Bacterial Pathogens: The Shigella Paradigm.

    PubMed

    Mellouk, Nora; Enninga, Jost

    2016-01-01

    Shigella is a Gram-negative bacterial pathogen, which causes bacillary dysentery in humans. A crucial step of Shigella infection is its invasion of epithelial cells. Using a type III secretion system, Shigella injects several bacterial effectors ultimately leading to bacterial internalization within a vacuole. Then, Shigella escapes rapidly from the vacuole, it replicates within the cytosol and spreads from cell-to-cell. The molecular mechanism of vacuolar rupture used by Shigella has been studied in some detail during the recent years and new paradigms are emerging about the underlying molecular events. For decades, bacterial effector proteins were portrayed as main actors inducing vacuolar rupture. This includes the effector/translocators IpaB and IpaC. More recently, this has been challenged and an implication of the host cell in the process of vacuolar rupture has been put forward. This includes the bacterial subversion of host trafficking regulators, such as the Rab GTPase Rab11. The involvement of the host in determining bacterial vacuolar integrity has also been found for other bacterial pathogens, particularly for Salmonella. Here, we will discuss our current view of host factor and pathogen effector implications during Shigella vacuolar rupture and the steps leading to it. PMID:27092296

  8. Structural and Chemical Profiling of the Human Cytosolic Sulfotransferases

    PubMed Central

    Allali-Hassani, Abdellah; Pan, Patricia W; Dombrovski, Ludmila; Najmanovich, Rafael; Tempel, Wolfram; Dong, Aiping; Loppnau, Peter; Martin, Fernando; Thonton, Janet; Edwards, Aled M; Bochkarev, Alexey; Plotnikov, Alexander N; Vedadi, Masoud; Arrowsmith, Cheryl H

    2007-01-01

    The human cytosolic sulfotransfases (hSULTs) comprise a family of 12 phase II enzymes involved in the metabolism of drugs and hormones, the bioactivation of carcinogens, and the detoxification of xenobiotics. Knowledge of the structural and mechanistic basis of substrate specificity and activity is crucial for understanding steroid and hormone metabolism, drug sensitivity, pharmacogenomics, and response to environmental toxins. We have determined the crystal structures of five hSULTs for which structural information was lacking, and screened nine of the 12 hSULTs for binding and activity toward a panel of potential substrates and inhibitors, revealing unique “chemical fingerprints” for each protein. The family-wide analysis of the screening and structural data provides a comprehensive, high-level view of the determinants of substrate binding, the mechanisms of inhibition by substrates and environmental toxins, and the functions of the orphan family members SULT1C3 and SULT4A1. Evidence is provided for structural “priming” of the enzyme active site by cofactor binding, which influences the spectrum of small molecules that can bind to each enzyme. The data help explain substrate promiscuity in this family and, at the same time, reveal new similarities between hSULT family members that were previously unrecognized by sequence or structure comparison alone. PMID:17425406

  9. Cytosolic Access of Intracellular Bacterial Pathogens: The Shigella Paradigm

    PubMed Central

    Mellouk, Nora; Enninga, Jost

    2016-01-01

    Shigella is a Gram-negative bacterial pathogen, which causes bacillary dysentery in humans. A crucial step of Shigella infection is its invasion of epithelial cells. Using a type III secretion system, Shigella injects several bacterial effectors ultimately leading to bacterial internalization within a vacuole. Then, Shigella escapes rapidly from the vacuole, it replicates within the cytosol and spreads from cell-to-cell. The molecular mechanism of vacuolar rupture used by Shigella has been studied in some detail during the recent years and new paradigms are emerging about the underlying molecular events. For decades, bacterial effector proteins were portrayed as main actors inducing vacuolar rupture. This includes the effector/translocators IpaB and IpaC. More recently, this has been challenged and an implication of the host cell in the process of vacuolar rupture has been put forward. This includes the bacterial subversion of host trafficking regulators, such as the Rab GTPase Rab11. The involvement of the host in determining bacterial vacuolar integrity has also been found for other bacterial pathogens, particularly for Salmonella. Here, we will discuss our current view of host factor and pathogen effector implications during Shigella vacuolar rupture and the steps leading to it. PMID:27092296

  10. Regulation of the cytosolic sulfotransferases by nuclear receptors

    PubMed Central

    Runge-Morris, Melissa; Kocarek, Thomas A.; Falany, Charles N.

    2013-01-01

    The cytosolic sulfotransferases (SULTs) are a multigene family of enzymes that catalyze the transfer of a sulfonate group from the physiologic sulfate donor, 3′-phosphoadenosine-5′-phosphosulfate, to a nucleophilic substrate to generate a polar product that is more amenable to elimination from the body. As catalysts of both xenobiotic and endogenous metabolism, the SULTs are major points of contact between the external and physiological environments, and modulation of SULT-catalyzed metabolism can not only affect xenobiotic disposition, but it can also alter endogenous metabolic processes. Therefore, it is not surprising that SULT expression is regulated by numerous members of the nuclear receptor (NR) superfamily that function as sensors of xenobiotics as well as endogenous molecules, such as fatty acids, bile acids, and oxysterols. These NRs include the peroxisome proliferator-activated receptors, pregnane X receptor, constitutive androstane receptor, vitamin D receptor, liver X receptors, farnesoid X receptor, retinoid-related orphan receptors, and estrogen-related receptors. This review summarizes current information about NR regulation of SULT expression. Because species differences in SULT subfamily composition and tissue-, sex-, development-, and inducer-dependent regulation are prominent, these differences will be emphasized throughout the review. In addition, because of the central role of the SULTs in cellular physiology, the effect of NR-mediated SULT regulation on physiological and pathophysiological processes will be discussed. Gaps in current knowledge that require further investigation are also highlighted. PMID:23330539

  11. Cytosolic phospholipase A2: physiological function and role in disease

    PubMed Central

    Leslie, Christina C.

    2015-01-01

    The group IV phospholipase A2 (PLA2) family is comprised of six intracellular enzymes (GIVA, -B, -C, -D, -E, and -F) commonly referred to as cytosolic PLA2 (cPLA2)α, -β, -γ, -δ, -ε, and -ζ. They contain a Ser-Asp catalytic dyad and all except cPLA2γ have a C2 domain, but differences in their catalytic activities and subcellular localization suggest unique regulation and function. With the exception of cPLA2α, the focus of this review, little is known about the in vivo function of group IV enzymes. cPLA2α catalyzes the hydrolysis of phospholipids to arachidonic acid and lysophospholipids that are precursors of numerous bioactive lipids. The regulation of cPLA2α is complex, involving transcriptional and posttranslational processes, particularly increases in calcium and phosphorylation. cPLA2α is a highly conserved widely expressed enzyme that promotes lipid mediator production in human and rodent cells from a variety of tissues. The diverse bioactive lipids produced as a result of cPLA2α activation regulate normal physiological processes and disease pathogenesis in many organ systems, as shown using cPLA2α KO mice. However, humans recently identified with cPLA2α deficiency exhibit more pronounced effects on health than observed in mice lacking cPLA2α, indicating that much remains to be learned about this interesting enzyme. PMID:25838312

  12. Urocortin 3 elevates cytosolic calcium in nucleus ambiguus neurons.

    PubMed

    Brailoiu, G Cristina; Deliu, Elena; Tica, Andrei A; Chitravanshi, Vineet C; Brailoiu, Eugen

    2012-09-01

    Urocortin 3 (also known as stresscopin) is an endogenous ligand for the corticotropin-releasing factor receptor 2 (CRF(2)). Despite predominant G(s) coupling of CRF(2), promiscuous coupling with other G proteins has been also associated with the activation of this receptor. As urocortin 3 has been involved in central cardiovascular regulation at hypothalamic and medullary sites, we examined its cellular effects on cardiac vagal neurons of nucleus ambiguus, a key area for the autonomic control of heart rate. Urocortin 3 (1 nM-1000 nM) induced a concentration-dependent increase in cytosolic Ca(2+) concentration that was blocked by the CRF(2) antagonist K41498. In the case of two consecutive treatments with urocortin 3, the second urocortin 3-induced Ca(2+) response was reduced, indicating receptor desensitization. The effect of urocortin 3 was abolished by pre-treatment with pertussis toxin and by inhibition of phospolipase C with U-73122. Urocortin 3 activated Ca(2+) influx via voltage-gated P/Q-type channels as well as Ca(2+) release from endoplasmic reticulum. Urocortin 3 promoted Ca(2+) release via inositol 1,4,5 trisphosphate receptors, but not ryanodine receptors. Our results indicate a novel Ca(2+) -mobilizing effect of urocortin 3 in vagal pre-ganglionic neurons of nucleus ambiguus, providing a cellular mechanism for a previously reported role for this peptide in parasympathetic cardiac regulation.

  13. Cytosolic calcium regulation in rat afferent vagal neurons during anoxia.

    PubMed

    Henrich, Michael; Buckler, Keith J

    2013-12-01

    Sensory neurons are able to detect tissue ischaemia and both transmit information to the brainstem as well as release local vasoactive mediators. Their ability to sense tissue ischaemia is assumed to be primarily mediated through proton sensing ion channels, lack of oxygen however may also affect sensory neuron function. In this study we investigated the effects of anoxia on isolated capsaicin sensitive neurons from rat nodose ganglion. Acute anoxia triggered a reversible increase in [Ca2+]i that was mainly due to Ca2+-efflux from FCCP sensitive stores and from caffeine and CPA sensitive ER stores. Prolonged anoxia resulted in complete depletion of ER Ca2+-stores. Mitochondria were partially depolarised by acute anoxia but mitochondrial Ca2+-uptake/buffering during voltage-gated Ca2+-influx was unaffected. The process of Ca2+-release from mitochondria and cytosolic Ca2+-clearance following Ca2+ influx was however significantly slowed. Anoxia was also found to inhibit SERCA activity and, to a lesser extent, PMCA activity. Hence, anoxia has multiple influences on [Ca2+]i homeostasis in vagal afferent neurons, including depression of ATP-driven Ca2+-pumps, modulation of the kinetics of mitochondrial Ca2+ buffering/release and Ca2+-release from, and depletion of, internal Ca2+-stores. These effects are likely to influence sensory neuronal function during ischaemia. PMID:24189167

  14. Biosynthesis of hydroxycinnamate conjugates: Implications for sustainable biomass and biofuel production

    SciTech Connect

    Liu C. J.

    2010-09-01

    Hydroxycinnamic acids constitute a large class of phenylpropanoid metabolites that are distributed ubiquitously in terrestrial plants. They occur most frequently as esters, amides or glycosides within the cytosol, the particular subcellular compartments such as the vacuole or the cell wall. Hydroxycinnamate conjugates play a vital role in the plant's growth and development and in its defense responses against biotic- and abiotic-stresses. Furthermore, the incorporation of hydroxycinnamate conjugates into the cell wall is a major factor attenuating the wall's biodegradability. Understanding the biosyntheses of hydroxycinnamate conjugates and its molecular regulation may well facilitate the sustainable production of cell wall biomass, and the efficient conversion of lignocellulosic materials. This paper reviews our current molecular and biochemical understandings on the formation of several classes of hydroxycinnamate esters and amides, including the soluble conjugates and the 'wall-bound' phenolics. It also discusses the emerging biotechnological applications in manipulating hydroxycinnamates to improve the degradability of the cell wall biomass and enhance the production of valuable chemicals and biomaterials.

  15. Antimony(v) cations for the selective catalytic transformation of aldehydes into symmetric ethers, α,β-unsaturated aldehydes, and 1,3,5-trioxanes.

    PubMed

    Arias Ugarte, Renzo; Devarajan, Deepa; Mushinski, Ryan M; Hudnall, Todd W

    2016-07-01

    1-Diphenylphosphinonaphthyl-8-triphenylstibonium triflate ([][OTf]) was prepared in excellent yield by treating 1-lithio-8-diphenylphosphinonaphthalene with dibromotriphenylstiborane followed by halide abstraction with AgOTf. This antimony(v) cation was found to be stable toward oxygen and water, and exhibited exceptional Lewis acidity. The Lewis acidity of [][OTf] was exploited in the catalytic reductive coupling of a variety of aldehydes into symmetric ethers of type in good to excellent yields under mild conditions using Et3SiH as the reductant. Additionally, [][OTf] was found to selectively catalyze the Aldol condensation reaction to afford α-β unsaturated aldehydes () when aldehydes with 2 α-hydrogen atoms were used. Finally, [][OTf] catalyzed the cyclotrimerization of aliphatic and aromatic aldehydes to afford the industrially-useful 1,3,5 trioxanes () in good yields, and with great selectivity. This phosphine-stibonium motif represents one of the first catalytic systems of its kind that is able to catalyze these reactions with aldehydes in a controlled, efficient manner. The mechanism of these processes has been explored both experimentally and theoretically. In all cases the Lewis acidic nature of the antimony(v) cation was found to promote these reactions. PMID:27326797

  16. A SeCSe-Pd(II) pincer complex as a highly efficient catalyst for allylation of aldehydes with allyltributyltin.

    PubMed

    Yao, Qingwei; Sheets, Matthew

    2006-07-01

    An air- and moisture-stable SeCSe-Pd(II) pincer complex was synthesized and found to catalyze the nucleophilic allylation of aldehydes with allyltributyltin. The allylation of a variety of aromatic and aliphatic aldehydes to give the corresponding homoallyl alcohols was performed at room temperature to 60 degrees C in yields ranging from 50% (for typical aliphatic aldehydes) to up to 97% (for aromatic aldehydes) using 5 x 10(-3) to 1 mol % of the Pd catalyst. NMR spectroscopic study indicated that a sigma-allylpalladium intermediate was formed and possibly functions as the nucleophilic species that undergoes addition to the aldehydes. PMID:16808533

  17. A SeCSe-Pd(II) pincer complex as a highly efficient catalyst for allylation of aldehydes with allyltributyltin.

    PubMed

    Yao, Qingwei; Sheets, Matthew

    2006-07-01

    An air- and moisture-stable SeCSe-Pd(II) pincer complex was synthesized and found to catalyze the nucleophilic allylation of aldehydes with allyltributyltin. The allylation of a variety of aromatic and aliphatic aldehydes to give the corresponding homoallyl alcohols was performed at room temperature to 60 degrees C in yields ranging from 50% (for typical aliphatic aldehydes) to up to 97% (for aromatic aldehydes) using 5 x 10(-3) to 1 mol % of the Pd catalyst. NMR spectroscopic study indicated that a sigma-allylpalladium intermediate was formed and possibly functions as the nucleophilic species that undergoes addition to the aldehydes.

  18. Arabidopsis aldehyde dehydrogenase 10 family members confer salt tolerance through putrescine-derived 4-aminobutyrate (GABA) production

    PubMed Central

    Zarei, Adel; Trobacher, Christopher P.; Shelp, Barry J.

    2016-01-01

    Polyamines represent a potential source of 4-aminobutyrate (GABA) in plants exposed to abiotic stress. Terminal catabolism of putrescine in Arabidopsis thaliana involves amine oxidase and the production of 4-aminobutanal, which is a substrate for NAD+-dependent aminoaldehyde dehydrogenase (AMADH). Here, two AMADH homologs were chosen (AtALDH10A8 and AtALDH10A9) as candidates for encoding 4-aminobutanal dehydrogenase activity for GABA synthesis. The two genes were cloned and soluble recombinant proteins were produced in Escherichia coli. The pH optima for activity and catalytic efficiency of recombinant AtALDH10A8 with 3-aminopropanal as substrate was 10.5 and 8.5, respectively, whereas the optima for AtALDH10A9 were approximately 9.5. Maximal activity and catalytic efficiency were obtained with NAD+ and 3-aminopropanal, followed by 4-aminobutanal; negligible activity was obtained with betaine aldehyde. NAD+ reduction was accompanied by the production of GABA and β-alanine, respectively, with 4-aminobutanal and 3-aminopropanal as substrates. Transient co-expression systems using Arabidopsis cell suspension protoplasts or onion epidermal cells and several organelle markers revealed that AtALDH10A9 was peroxisomal, but AtALDH10A8 was cytosolic, although the N-terminal 140 amino acid sequence of AtALDH10A8 localized to the plastid. Root growth of single loss-of-function mutants was more sensitive to salinity than wild-type plants, and this was accompanied by reduced GABA accumulation. PMID:27725774

  19. Zinc-Catalyzed Dehydrogenative Cross-Coupling of Terminal Alkynes with Aldehydes: Access to Ynones.

    PubMed

    Tang, Shan; Zeng, Li; Liu, Yichang; Lei, Aiwen

    2015-12-21

    Because of the lack of redox ability, zinc has seldom been used as a catalyst in dehydrogenative cross-coupling reactions. Herein, a novel zinc-catalyzed dehydrogenative C(sp(2) )H/C(sp)H cross-coupling of terminal alkynes with aldehydes was developed, and provides a simple way to access ynones from readily available materials under mild reaction conditions. Good reaction selectivity can be achieved with a 1:1 ratio of terminal alkyne and aldehyde. Various terminal alkynes and aldehydes are suitable in this transformation. PMID:26564779

  20. Direct Access to β-Fluorinated Aldehydes by Nitrite-Modified Wacker Oxidation.

    PubMed

    Chu, Crystal K; Ziegler, Daniel T; Carr, Brian; Wickens, Zachary K; Grubbs, Robert H

    2016-07-11

    An aldehyde-selective Wacker-type oxidation of allylic fluorides proceeds with a nitrite catalyst. The method represents a direct route to prepare β-fluorinated aldehydes. Allylic fluorides bearing a variety of functional groups are transformed in high yield and very high regioselectivity. Additionally, the unpurified aldehyde products serve as versatile intermediates, thus enabling access to a diverse array of fluorinated building blocks. Preliminary mechanistic investigations suggest that inductive effects have a strong influence on the rate and regioselectivity of the oxidation. PMID:27225538

  1. Direct Access to β-Fluorinated Aldehydes by Nitrite-Modified Wacker Oxidation.

    PubMed

    Chu, Crystal K; Ziegler, Daniel T; Carr, Brian; Wickens, Zachary K; Grubbs, Robert H

    2016-07-11

    An aldehyde-selective Wacker-type oxidation of allylic fluorides proceeds with a nitrite catalyst. The method represents a direct route to prepare β-fluorinated aldehydes. Allylic fluorides bearing a variety of functional groups are transformed in high yield and very high regioselectivity. Additionally, the unpurified aldehyde products serve as versatile intermediates, thus enabling access to a diverse array of fluorinated building blocks. Preliminary mechanistic investigations suggest that inductive effects have a strong influence on the rate and regioselectivity of the oxidation.

  2. Transformations of several monoterpenoids in the presence of aldehydes in supercritical solvents

    NASA Astrophysics Data System (ADS)

    Anikeev, V. I.; Sivcev, V. P.; Il'ina, I. V.; Korchagina, D. V.; Statsenko, O. B.; Volcho, K. P.; Salakhutdinov, N. F.

    2013-03-01

    The reactivity of verbenol epoxide and isopulegol in supercritical solvents in the presence of aromatic aldehydes was studied using a flow type reactor and a heterogeneous catalyst (Al2O3) or no catalyst. The intramolecular transformations or interactions of reagents with the solvent prevailed in all cases; the yield of the products of intermolecular reactions of terpenoids with aldehydes was up to 1%. The aldehydes did not interact with verbenol epoxide but produced a considerable effect on the distribution of its isomerization products.

  3. Cysteine S-conjugate β-lyases: Important roles in the metabolism of naturally occurring sulfur and selenium-containing compounds, xenobiotics and anticancer agents

    PubMed Central

    Cooper, Arthur J. L.; Krasnikov, Boris F.; Niatsetskaya, Zoya V.; Pinto, John T.; Callery, Patrick S.; Villar, Maria T.; Artigues, Antonio; Bruschi, Sam A.

    2010-01-01

    Summary Cysteine S-conjugate β-lyases are pyridoxal 5′-phosphate-containing enzymes that catalyze β-elimination reactions with cysteine S-conjugates that possess a good leaving group in the β-position. The end products are aminoacrylate and a sulfur-containing fragment. The aminoacrylate tautomerizes and hydrolyzes to pyruvate and ammonia. The mammalian cysteine S-conjugate β-lyases thus far identified are enzymes involved in amino acid metabolism that catalyze β-lyase reactions as non-physiological side reactions. Most are aminotransferases. In some cases the lyase is inactivated by reaction products. The cysteine S-conjugate β-lyases are of much interest to toxicologists because they play an important key role in the bioactivation (toxication) of halogenated alkenes, some of which are produced on an industrial scale and are environmental contaminants. The cysteine S-conjugate β-lyases have been reviewed in this journal previously [Cooper and Pinto, 2006]. Here we focus on more recent findings regarding: 1) the identification of enzymes associated with high-Mr cysteine S-conjugate β-lyases in the cytosolic and mitochondrial fractions of rat liver and kidney; 2) the mechanism of syncatalytic inactivation of rat liver mitochondrial aspartate aminotransferase by the nephrotoxic β-lyase substrate S-(1,1,2,2-tetrafluoroethyl)-L-cysteine (the cysteine S-conjugate of tetrafluoroethylene); 3) toxicant channeling of reactive fragments from the active site of mitochondrial aspartate aminotransferase to susceptible proteins in the mitochondria; 4) the involvement of cysteine S-conjugate β-lyases in the metabolism/bioactivation of drugs and natural products; and 5) the role of cysteine S-conjugate β-lyases in the metabolism of selenocysteine Se-conjugates. This review emphasizes the fact that the cysteine S-conjugate β-lyases are biologically more important than hitherto appreciated. PMID:20306345

  4. Cysteine S-conjugate β-lyases: important roles in the metabolism of naturally occurring sulfur and selenium-containing compounds, xenobiotics and anticancer agents.

    PubMed

    Cooper, Arthur J L; Krasnikov, Boris F; Niatsetskaya, Zoya V; Pinto, John T; Callery, Patrick S; Villar, Maria T; Artigues, Antonio; Bruschi, Sam A

    2011-06-01

    Cysteine S-conjugate β-lyases are pyridoxal 5'-phosphate-containing enzymes that catalyze β-elimination reactions with cysteine S-conjugates that possess a good leaving group in the β-position. The end products are aminoacrylate and a sulfur-containing fragment. The aminoacrylate tautomerizes and hydrolyzes to pyruvate and ammonia. The mammalian cysteine S-conjugate β-lyases thus far identified are enzymes involved in amino acid metabolism that catalyze β-lyase reactions as non-physiological side reactions. Most are aminotransferases. In some cases the lyase is inactivated by reaction products. The cysteine S-conjugate β-lyases are of much interest to toxicologists because they play an important key role in the bioactivation (toxication) of halogenated alkenes, some of which are produced on an industrial scale and are environmental contaminants. The cysteine S-conjugate β-lyases have been reviewed in this journal previously (Cooper and Pinto in Amino Acids 30:1-15, 2006). Here, we focus on more recent findings regarding: (1) the identification of enzymes associated with high-M(r) cysteine S-conjugate β-lyases in the cytosolic and mitochondrial fractions of rat liver and kidney; (2) the mechanism of syncatalytic inactivation of rat liver mitochondrial aspartate aminotransferase by the nephrotoxic β-lyase substrate S-(1,1,2,2-tetrafluoroethyl)-L-cysteine (the cysteine S-conjugate of tetrafluoroethylene); (3) toxicant channeling of reactive fragments from the active site of mitochondrial aspartate aminotransferase to susceptible proteins in the mitochondria; (4) the involvement of cysteine S-conjugate β-lyases in the metabolism/bioactivation of drugs and natural products; and (5) the role of cysteine S-conjugate β-lyases in the metabolism of selenocysteine Se-conjugates. This review emphasizes the fact that the cysteine S-conjugate β-lyases are biologically more important than hitherto appreciated.

  5. Copurification of cytosolic fructose-1,6-bisphosphatase and cytosolic aldolase from endosperm of germinating castor oil seeds.

    PubMed

    Moorhead, G B; Hodgson, R J; Plaxton, W C

    1994-08-01

    The cytosolic isozymes of fructose-1,6-bisphosphatase (FBPasec) and aldolase (ALDc) from germinating castor oil seed endosperm (COS) (Ricinus communis L.; cv Hale) were purified to homogeneity and final specific activities 49 and 2.8 (mumol product produced/min)/mg protein, respectively. Nondenaturing polyacrylamide gel electrophoresis of the final FBPasec preparation resolved a single protein-staining band which comigrated with FBPase activity. Two protein-staining bands of 41 and 39 kDa that occurred in an approximate 1:1 ratio were observed following sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the final FBPasec preparation. Rabbit anti-(FBPasec) immune serum immunoprecipitated the activities of FBPasec, but not that of the plastidic isozyme of FBPase from germinated COS. Immunoblot analysis utilizing affinity purified anti-(COS FBPasec) immunoglobulin G established that the 39-kDa subunit of FBP-asec did not arise via proteolytic cleavage of the 41-kDa subunit during tissue extraction and enzyme purification. However, FBPasec was susceptible to degradation by endogenous protease(s) during incubation of an acidic (pH 5.9) clarified COS extract at 25 degrees C. This proteolysis caused the production of a 32-kDa antigenic polypeptide and resulted in FBPase inactivation. Gel filtration indicated that purified FBPasec exists in at least 8 different oligomeric forms ranging in size from > 2 million to < 34 kDa. The majority of FBPasec, however, eluted as a 143-kDa heterotetramer. Sodium dodecyl sulfate gel electrophoresis of the final ALDc preparation yielded a single 40-kDa protein-staining polypeptide that cross-reacted with anti-(carrot ALDc) IgG. FBPasec copurified with ALDc through polyethylene glycol fractionation, Q-Sepharose, and phosphocellulose chromatographies, and the intensity of the fluorescence emission spectrum of ALDc was greatly reduced in the presence of COS FBPasec, but not rabbit muscle FBPase. These findings suggest that these

  6. Self-assembled nanoparticles from hyaluronic acid-paclitaxel prodrugs for direct cytosolic delivery and enhanced antitumor activity.

    PubMed

    Xu, Chaoran; He, Wei; Lv, Yaqi; Qin, Chao; Shen, Lingjia; Yin, Lifang

    2015-09-30

    A prodrug-based nanosystem obtained by formulating prodrug and nanotechnology into a system is one of the most promising strategies to enhance drug delivery for disease treatment. Herein, we report a new nanosystem based on HA-PTX conjugates (HA-PTX Ns), which penetrated across cell membranes into cytosol, thus enhancing paclitaxel (PTX) delivery. HA-PTX Ns were successfully obtained based on HA-PTX, and their average particle size was approximately 200 nm. Importantly, unlike other prodrug-based nanosystems, HA-PTX Ns obtained cellular entry without entrapment within the lysosomal-endosomal system by using pathways including clathrin-mediated endocytosis, microtubule-associated internalization, macropinocytosis and cholesterol-dependence. Due to significant accumulation in tumors, HA-PTX Ns had more than a 4-fold decrease in tumor volume on day 14 in contrast with PTX alone. In conclusion, HA-PTX Ns could enter cells, bypass the lysosomal-endosomal system and improve PTX delivery. PMID:26232702

  7. Francisella Inflammasomes: Integrated Responses to a Cytosolic Stealth Bacterium.

    PubMed

    Wallet, Pierre; Lagrange, Brice; Henry, Thomas

    2016-01-01

    Francisella tularensis is a facultative intracellular bacterium causing tularemia, a zoonotic disease. Francisella replicates in the macrophage cytosol and eventually triggers cytosolic immune responses. In murine macrophages, Francisella novicida and Francisella tularensis live vaccine strain lyse in the host cytosol and activate the cytosolic DNA receptor Aim2. Here, we review the mechanisms leading or contributing to Aim2 inflammasome activation, including the role of TLRs and of IFN signaling and the implication of the guanylate-binding proteins 2 and 5 in triggering cytosolic bacteriolysis. Furthermore, we present how this cytosolic Gram-negative bacterium escapes recognition by caspase-11 but can trigger a non-canonical caspase-8 inflammasome. In addition, we highlight the differences in inflammasome activation in murine and human cells with pyrin, NLRP3, and AIM2 involved in sensing Francisella in human phagocytes. From a bacterial prospective, we describe the hiding strategy of Francisella to escape recognition by innate sensors and to resist to bacteriolysis in the host cytosol. Finally, we discuss the inability of the inflammasome sensors to detect F. tularensis subspecies tularensis strains, making them highly pathogenic stealth microbes.

  8. The cytosolic tail of the tumor marker protein Trop2 - a structural switch triggered by phosphorylation

    NASA Astrophysics Data System (ADS)

    Pavšič, Miha; Ilc, Gregor; Vidmar, Tilen; Plavec, Janez; Lenarčič, Brigita

    2015-05-01

    Trop2 is a transmembrane signaling glycoprotein upregulated in stem and carcinoma cells. Proliferation-enhancing signaling involves regulated intramembrane proteolytic release of a short cytoplasmic fragment, which is later engaged in a cytosolic signaling complex. We propose that Trop2 function is modulated by phosphorylation of a specific serine residue within this cytosolic region (Ser303), and by proximity effects exerted on the cytosolic tail by Trop2 dimerization. Structural characterization of both the transmembrane (Trop2TM) and cytosolic regions (Trop2IC) support this hypothesis, and shows that the central region of Trop2IC forms an α-helix. Comparison of NMR structures of non-phosphorylated and phosphorylated forms suggest that phosphorylation of Trop2IC triggers salt bridge reshuffling, resulting in significant conformational changes including ordering of the C-terminal tail. In addition, we demonstrate that the cytosolic regions of two Trop2 subunits can be brought into close proximity via transmembrane part dimerization. Finally, we show that Ser303-phosphorylation significantly affects the structure and accessibility of functionally important regions of the cytosolic tail. These observed structural features of Trop2 at the membrane-cytosol interface could be important for regulation of Trop2 signaling activity.

  9. Intracellular pH (pHin) and cytosolic calcium ([Ca2+]cyt) regulation via ATPases: studies in cell populations, single cells, and subcellular compartments

    NASA Astrophysics Data System (ADS)

    Rojas, Jose D.; Sanka, Shankar C.; Gyorke, Sandor; Wesson, Donald E.; Minta, Akwasi; Martinez-Zaguilan, Raul

    1999-07-01

    Changes in pHin and (Ca2+)cyt are important in the signal transduction mechanisms leading to many physiological responses including cell growth, motility, secretion/exocytosis, etc. The concentrations of these ions are regulated via primary and secondary ion transporting mechanisms. In diabetes, specific pH and Ca2+ regulatory mechanism might be altered. To study these ions, we employ fluorescence spectroscopy, and cell imagin spectroscopy/confocal microscopy. pH and Ca2+ indicators are loaded in the cytosol with acetoxymethyl ester forms of dyes, and in endosomal/lysosomal (E/L) compartments by overnight incubation of cells with dextran- conjugated ion fluorescent probes. We focus on specific pH and Ca2+ regulatory systems: plasmalemmal vacuolar- type H+-ATPases (pm V-ATPases) and sarcoplasmic/endoplasmic reticulum Ca2+-ATPases (SERCA). As experimental models, we employ vascular smooth muscle (VSM) and microvascular endothelial cells. We have chosen these cells because they are important in blood flow regulation and in angiogenesis. These processes are altered in diabetes. In many cell types, ion transport processes are dependent on metabolism of glucose for maximal activity. Our main findings are: (a) glycolysis coupling the activity of SERCA is required for cytosolic Ca2+ homeostasis in both VSM and microvascular endothelial cells; (b) E/L compartments are important for pH and Ca2+ regulation via H+-ATPases and SERCA, respectively; and (c) pm-V- ATPases are important for pHin regulation in microvascular endothelial cells.

  10. Involvement of cytosolic Cl- in osmoregulation of alpha-ENaC gene expression.

    PubMed

    Niisato, Naomi; Eaton, Douglas C; Marunaka, Yoshinori

    2004-11-01

    Hypotonicity stimulates transepithelial Na(+) reabsorption in renal A6 cells, but the mechanism for this stimulation is not fully understood. In the present study, we found that hypotonicity stimulated Na(+) reabsorption through increases in mRNA expression of the alpha-subunit of the epithelial Na(+) channel (alpha-ENaC). Hypotonicity decreases cytosolic Cl(-) concentration; therefore, we hypothesized that hypotonicity-induced decreases in cytosolic Cl(-) concentration could act as a signal to regulate Na(+) reabsorption through changes in alpha-ENaC mRNA expression. Treatment with the flavone apigenin, which activates the Na(+)-K(+)-2Cl(-) cotransporter and increases cytosolic Cl(-) concentration, markedly suppressed the hypotonicity-induced increase in alpha-ENaC mRNA expression. On the other hand, blockade of the Na(+)-K(+)-2Cl(-) cotransporter decreases cytosolic Cl(-) concentration and increased alpha-ENaC mRNA expression and Na(+) reabsorption. Blocking Cl(-) channels with 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB) inhibited the hypotonicity-induced decrease in cytosolic Cl(-) concentration and suppressed the hypotonicity-induced increase in alpha-ENaC mRNA expression. Coapplication of NPPB and apigenin synergistically suppressed alpha-ENaC mRNA expression. Thus, in every case, changes in cytosolic Cl(-) concentration were associated with changes in alpha-ENaC mRNA expression and changes in Na(+) reabsorption: decreases in cytosolic Cl(-) concentration increased alpha-ENaC mRNA and increased Na(+) reabsorption, whereas increases in cytosolic Cl(-) concentration decreased alpha-ENaC mRNA and decreased Na(+) reabsorption. These findings support the hypothesis that changes in cytosolic Cl(-) concentration are an important and novel signal in hypotonicity-induced regulation of alpha-ENaC expression and Na(+) reabsorption. PMID:15292045

  11. Trypanosoma cruzi cytosolic alkaline antigens (FI) induce polyclonal activation in murine normal B cells.

    PubMed

    Montes, C L; Vottero-Cima, E; Gruppi, A

    1996-08-01

    Several reports have described polyclonal activation in mice acutely infected with Trypanosoma cruzi. The aim of this work was to analyse the participation of one T. cruzi antigenic fraction in this immunological event. The antigen selected was FI, an antigenic fraction of pI 7-9 obtained from T. cruzi cytosol separated by isoelectricfocusing. FI is constituted by molecules with molecular weights of around 60 and 20 KDa. The authors assayed the ability of this antigenic fraction to induce polyclonal activation of spleen mononuclear cells from normal (NSMC) BALB/c mice. NSMC showed a marked lymphoproliferative response measured by 3H-thymidine incorporation after 3 days of culture in presence of FI. The values reached by FI-stimulated cells were 10 times higher than the controls (non-stimulated cells). This effect was dose-dependent. Furthermore, the authors observed that a purified T-cell population in the presence of adherent cells was unaffected by FI. Additionally, in a culture of NSMC, FI stimulated the proliferation of B cells as observed by the increase of the percentage of B220+ cells determined by FACS using FITC-conjugated anti-mouse B220. The authors noticed that the percentage of B220+Ly1+(CD5) populations in the presence of FI did not change with respect to the control (non-stimulated cells), indicating that FI expanded both conventional and CD5+ B cells. The isotypic pattern of the antibodies produced after 6 days of culture of NSMC in the presence of FI was predominantly IgM, which reacted with highly conserved antigens such as actin, myosin, myoglobin, thyroglobulin and carbonic anhydrase, but did not react with FI. A slight increase of IgG1 and IgG3 with respect to the control was observed but no changes on the levels of IgG2 was noticed. These results indicate that FI promotes activation, proliferation and differentiation in antibody-secreting cells of normal murine B lymphocytes.

  12. Cytosolic PrP Can Participate in Prion-Mediated Toxicity

    PubMed Central

    Thackray, Alana M.; Zhang, Chang; Arndt, Tina

    2014-01-01

    ABSTRACT Prion diseases are characterized by a conformational change in the normal host protein PrPC. While the majority of mature PrPC is tethered to the plasma membrane by a glycosylphosphatidylinositol anchor, topological variants of this protein can arise during its biosynthesis. Here we have generated Drosophila transgenic for cytosolic ovine PrP in order to investigate its toxic potential in flies in the absence or presence of exogenous ovine prions. While cytosolic ovine PrP expressed in Drosophila was predominantly detergent insoluble and showed resistance to low concentrations of proteinase K, it was not overtly detrimental to the flies. However, Drosophila transgenic for cytosolic PrP expression exposed to classical or atypical scrapie prion inocula showed a faster decrease in locomotor activity than similar flies exposed to scrapie-free material. The susceptibility to classical scrapie inocula could be assessed in Drosophila transgenic for panneuronal expression of cytosolic PrP, whereas susceptibility to atypical scrapie required ubiquitous PrP expression. Significantly, the toxic phenotype induced by ovine scrapie in cytosolic PrP transgenic Drosophila was transmissible to recipient PrP transgenic flies. These data show that while cytosolic PrP expression does not adversely affect Drosophila, this topological PrP variant can participate in the generation of transmissible scrapie-induced toxicity. These observations also show that PrP transgenic Drosophila are susceptible to classical and atypical scrapie prion strains and highlight the utility of this invertebrate host as a model of mammalian prion disease. IMPORTANCE During prion diseases, the host protein PrPC converts into an abnormal conformer, PrPSc, a process coupled to the generation of transmissible prions and neurotoxicity. While PrPC is principally a glycosylphosphatidylinositol-anchored membrane protein, the role of topological variants, such as cytosolic PrP, in prion-mediated toxicity and

  13. The cytosolic domain of human Tom22 modulates human Bax mitochondrial translocation and conformation in yeast.

    PubMed

    Renault, Thibaud T; Grandier-Vazeille, Xavier; Arokium, Hubert; Velours, Gisèle; Camougrand, Nadine; Priault, Muriel; Teijido, Oscar; Dejean, Laurent M; Manon, Stéphen

    2012-01-20

    The role of the mitochondrial protein receptor Tom22p in the interaction of pro-apoptotic protein Bax with yeast mitochondria was investigated. Co-immunoprecipitation assays showed that human Bax interacted with different TOM subunits, including Tom22p. Expression of the cytosolic receptor domain of human Tom22 increased Bax mitochondrial localization, but decreased the proportion of active Bax. BN-PAGE showed that the cytosolic domain of Tom22 interfered with the oligomerization of Bax. These data suggest that the interaction with the cytosolic domain of Tom22 helps Bax to acquire a conformation able to interact with the outer mitochondrial membrane. PMID:22198199

  14. The Cytosolic Domain of Pex22p Stimulates the Pex4p-Dependent Ubiquitination of the PTS1-Receptor

    PubMed Central

    El Magraoui, Fouzi; Schrötter, Andreas; Brinkmeier, Rebecca; Kunst, Lena; Mastalski, Thomas; Müller, Thorsten; Marcus, Katrin; Meyer, Helmut E.; Girzalsky, Wolfgang; Erdmann, Ralf; Platta, Harald W.

    2014-01-01

    Peroxisomal biogenesis is an ubiquitin-dependent process because the receptors required for the import of peroxisomal matrix proteins are controlled via their ubiquitination status. A key step is the monoubiquitination of the import receptor Pex5p by the ubiquitin-conjugating enzyme (E2) Pex4p. This monoubiquitination is supposed to take place after Pex5p has released the cargo into the peroxisomal matrix and primes Pex5p for the extraction from the membrane by the mechano-enzymes Pex1p/Pex6p. These two AAA-type ATPases export Pex5p back to the cytosol for further rounds of matrix protein import. Recently, it has been reported that the soluble Pex4p requires the interaction to its peroxisomal membrane-anchor Pex22p to display full activity. Here we demonstrate that the soluble C-terminal domain of Pex22p harbours its biological activity and that this activity is independent from its function as membrane-anchor of Pex4p. We show that Pex4p can be functionally fused to the trans-membrane segment of the membrane protein Pex3p, which is not directly involved in Pex5p-ubiquitination and matrix protein import. However, this Pex3(N)-Pex4p chimera can only complement the double-deletion strain pex4Δ/pex22Δ and ensure optimal Pex5p-ubiquitination when the C-terminal part of Pex22p is additionally expressed in the cell. Thus, while the membrane-bound portion Pex22(N)p is not required when Pex4p is fused to Pex3(N)p, the soluble Pex22(C)p is essential for peroxisomal biogenesis and efficient monoubiquitination of the import receptor Pex5p by the E3-ligase Pex12p in vivo and in vitro. The results merge into a picture of an ubiquitin-conjugating complex at the peroxisomal membrane consisting of three domains: the ubiquitin-conjugating domain (Pex4p), a membrane-anchor domain (Pex22(N)p) and an enhancing domain (Pex22(C)p), with the membrane-anchor domain being mutually exchangeable, while the Ubc- and enhancer-domains are essential. PMID:25162638

  15. Aldehydes from n-6 fatty acid peroxidation. Effects on aminophospholipids.

    PubMed

    Guichardant, M; Bernoud-Hubac, N; Chantegrel, B; Deshayes, C; Lagarde, M

    2002-01-01

    4-Hydroxy-nonenal (4-HNE) is a major by-product of n-6 fatty acid peroxidation. It has been described to covalently bind biomolecules expressing primary amine, especially the Lys residues in proteins. Low-density lipoproteins (LDL) are well-described macromolecules to be modified by 4-HNE, making them available to scavenger receptors on macrophages. Those macrophages then become foam cells and play an active role in atherogenesis. This paper reports on the covalent binding of 4-HNE to phosphatidylethanolamine (PE), a major aminophospholipid in biological membranes. In contrast, phosphatidylserine (PS) is virtually not modified by 4-HNE. One stable adduct, the Michael adduct PE/4-HNE is a poor substrate of secreted phospholipase A(2) and is not cleaved by phospholipase D. Plasmalogen PE, an important subclass of PE, is covalently modified by 4-HNE as well, but appears to be further degraded on its sn-1 position, the alkenyl chain, which might alter the antioxidant potential of the molecule. An aldehyde homologous to 4-HNE has been characterized as a breakdown product of 12-hydroperoxyeicosatetraenoic acid (12-HpETE) and named 4-hydroxy-2E,6Z-dodecadienal (4-HDDE). This compound as well as 4-HNE was detected in human plasma. Finally, 4-HDDE appears almost 3-fold more active than 4-HNE to make covalent adducts with PE. We conclude that 4-HNE and 4-HDDE are two biologically relevant markers of n-6 fatty acid peroxidation that may alter the phospholipid-dependent cell signaling.

  16. Mechanisms of alcohol liver damage: aldehydes, scavenger receptors, and autoimmunity.

    PubMed

    Duryee, Michael J; Willis, Monte S; Freeman, Thomas L; Kuszynski, Charles A; Tuma, Dean J; Klassen, Lynell W; Thiele, Geoffrey M

    2004-09-01

    While most of the investigations into the causative events in the development of alcoholic liver disease (ALD) have been focused on multiple factors, increasing interest has centered around the possible role of immune mechanisms in the pathogenesis and perpetuation of ALD. This is because many of the clinical features of ALD suggest that immune effector mechanisms may be contributing to liver tissue damage, as evidenced by the detection of circulating autoantibodies, and the presence of CD4+ and CD8+ lymphoid cells in the livers of patients with ALD. One mechanism that has been associated with the development of autoimmune responses is the modification (haptenation or adduction) of liver proteins with aldehydes or other products of oxidative stress. This is because it has been shown that these adducted proteins can induce specific immune responses, to the adduct, the adduct plus protein (conformational antigens), as well as the unmodified parts of the protein. More importantly, it is possible to demonstrate that adducted self-proteins can induce reactivity to the normal self-protein and thereby induce autoimmune responses. Therefore, it is the purpose of this manuscript to outline the mechanism(s) by which these modified self proteins can induce autoimmune reactivity, and thus play a role in the development and/or progression of ALD.

  17. Weak chemiluminescence of bilirubin and its stimulation by aldehydes.

    PubMed

    Watanabe, H; Usa, M; Kobayashi, M; Agatsuma, S; Inaba, H

    1992-01-01

    Bilirubin in an alkaline solution exhibits a weak chemiluminescence (CL) under aerobic conditions. This spontaneous CL was markedly enhanced by the addition of various aldehydes. The fluorescent emission spectrum of bilirubin, excited by weak intensity light at 350 nm, coincided with its CL emission spectrum (peak at 670 nm). CL emission from bilirubin was not quenched by active oxygen scavengers. This suggests that triplet oxygen reacts with bilirubin, and forms an oxygenated intermediate (hydroperoxide) as a primary emitter (oxidative scission of tetrapyrrole bonds in bilirubin is not involved in this CL). The Ehrlich reaction (test for monopyrroles) and hydrolsulphite reaction (test for dipyrroles) on the CL reaction mixture and unreacted bilirubin showed no differences. When the CL was initiated by singlet oxygen, rather than superoxide anion, monopyrrole, was detected in the reaction products by gel chromatography. The inhibitory effect of a scavenger of singlet oxygen on CL was eliminated in the presence of formaldehyde. Therefore, triplet carbonyl, formed by singlet oxygen through the dioxetane structure in bilirubin, is not an emitter. The reaction mechanism of bilirubin CL and the formation of a hydroperoxide intermediate is discussed in relation to the chemical structure of luciferin molecules from bioluminescent organisms.

  18. Does acute exposure to aldehydes impair pulmonary function and structure?

    PubMed

    Abreu, Mariana de; Neto, Alcendino Cândido; Carvalho, Giovanna; Casquillo, Natalia Vasconcelos; Carvalho, Niedja; Okuro, Renata; Ribeiro, Gabriel C Motta; Machado, Mariana; Cardozo, Aléxia; Silva, Aline Santos E; Barboza, Thiago; Vasconcellos, Luiz Ricardo; Rodrigues, Danielle Araujo; Camilo, Luciana; Carneiro, Leticia de A M; Jandre, Frederico; Pino, Alexandre V; Giannella-Neto, Antonio; Zin, Walter A; Corrêa, Leonardo Holanda Travassos; Souza, Marcio Nogueira de; Carvalho, Alysson R

    2016-07-15

    Mixtures of anhydrous ethyl alcohol and gasoline substituted for pure gasoline as a fuel in many Brazilian vehicles. Consequently, the concentrations of volatile organic compounds (VOCs) such as ketones, other organic compounds, and particularly aldehydes increased in many Brazilian cities. The current study aims to investigate whether formaldehyde, acetaldehyde, or mixtures of both impair lung function, morphology, inflammatory and redox responses at environmentally relevant concentrations. For such purpose, C57BL/6 mice were exposed to either medical compressed air or to 4 different mixtures of formaldehyde and acetaldehyde. Eight hours later animals were anesthetized, paralyzed and lung mechanics and morphology, inflammatory cells and IL-1β, KC, TNF-α, IL-6, CCL2, MCP-1 contents, superoxide dismutase and catalalase activities were determined. The extra pulmonary respiratory tract was also analyzed. No differences could be detected between any exposed and control groups. In conclusion, no morpho-functional alterations were detected in exposed mice in relation to the control group. PMID:27102012

  19. Characteristics of aldehyde dehydrogenase 2 (Aldh2) knockout mice.

    PubMed

    Yu, Hsu-Sheng; Oyama, Tsunehiro; Isse, Toyohi; Kitakawa, Kyoko; Ogawa, Masanori; Pham, Thi-Thu-Phuong; Kawamoto, Toshihiro

    2009-11-01

    Acetaldehyde is an intermediate of ethanol oxidation. It covalently binds to DNA, and is known as a carcinogen. Aldehyde dehydrogenase 2 (ALDH2) is an important enzyme that oxidizes acetaldehyde. Approximately 45% of Chinese and Japanese individuals have the inactive ALDH2 genotypes (ALDH2*2/*2 and ALDH2*1/*2), and Aldh2 knockout mice appear to be a valid animal model for humans with inactive ALDH2. This review gives an overview of published studies on Aldh2 knockout mice, which were treated with ethanol or acetaldehyde. According to these studies, it was found that Aldh2 -/- mice (Aldh2 knockout mice) are more susceptible to ethanol and acetaldehyde-induced toxicity than Aldh2 +/+ mice (wild type mice). When mice were fed with ethanol, the mortality was increased. When they were exposed to atmospheres containing acetaldehyde, the Aldh2 -/- mice showed more severe toxic symptoms, like weight loss and higher blood acetaldehyde levels, as compared with the Aldh2 +/+ mice. Thus, ethanol and acetaldehyde treatment affects Aldh2 knockout mice more than wild type mice. Based on these findings, it is suggested that ethanol consumption and acetaldehyde inhalation are inferred to pose a higher risk to ALDH2-inactive humans. These results also support that ALDH2-deficient humans who habitually consume alcohol have a higher rate of cancer than humans with functional ALDH2. PMID:19874182

  20. Aldehyde dehydrogenase induction in arsenic-exposed rat bladder epithelium.

    PubMed

    Huang, Ya-Chun; Yu, Hsin-Su; Chai, Chee-Yin

    2016-01-01

    Arsenic is widely distributed in the environment. Many human cancers, including urothelial carcinoma (UC), show a dose-dependent relationship with arsenic exposure in the south-west coast of Taiwan (also known as the blackfoot disease (BFD) areas). However, the molecular mechanisms of arsenic-mediated UC carcinogenesis has not yet been defined. In vivo study, the rat bladder epithelium were exposed with arsenic for 48 h. The proteins were extracted from untreated and arsenic-treated rat bladder cells and utilized two-dimensional gel electrophoresis and mass spectrometry. Selected peptides were extracted from the gel and identified by quadrupole-time of flight (Q-TOF) Ultima-Micromass spectra. The significantly difference expression of proteins in arsenic-treated groups as compared with untreated groups was confirmed by immunohistochemistry (IHC) and western blotting. We found that thirteen proteins were down-regulated and nine proteins were up-regulated in arsenic-treated rat bladder cells when compared with untreated groups. The IHC and western blotting results confirmed that aldehyde dehydrogenase (ALDH) protein was up-regulated in arsenic-treated rat bladder epithelium. Expression of ALDH protein was significantly higher in UC patients from BFD areas than those from non-BFD areas using IHC (p=0.018). In conclusion, the ALDH protein expression could be used as molecular markers for arsenic-induced transformation.

  1. Studies of the condensation of sulfones with ketones and aldehydes.

    PubMed

    Garst, Michael E; Dolby, Lloyd J; Esfandiari, Shervin; Okrent, Rachel A; Avey, Alfred A

    2006-01-20

    [reaction: see text] The condensation of ketones or aldehydes with sulfones was shown to give a variety of products. Condensation of 2-methylcyclohexanone with dimethyl sulfone using potassium t-butoxide as base gave useful yields of 1,2-dimethylenecyclohexane. Under the same conditions, cycloheptanone, 3-methyl-2-butanone, and 2-butanone were converted to dienes. Remarkably, these reaction conditions converted acetophenone into p-terphenyl (10%) and (E)-1,4-diphenyl-3-penten-1-one (44%). Propiophenone was converted to 2'-methyl-p-terphenyl (61%). Using alpha-tetralone produced 1-methynaphthalene and naphthalene. No reaction took place with beta-tetralone. Using diethyl sulfone with alpha-tetralone lead to pure naphthalene. Condensation of isobutyraldehyde and dimethyl sulfone using potassium t-butoxide gave isoprene in low yield. Using benzaldehyde and benzyl phenyl sulfone in N,N-dimethylacetamide gave 1,2-diphenyl-1-phenylsulfonylethylene, N,N-dimethylcinnamide, and a complex condensation product. Only 1,2-diphenyl-1-phenylsulfonylethylene was obtained when the solvent was THF. PMID:16408963

  2. metal ion interactions of picoline-2-aldehyde thiosemicarbazone.

    PubMed

    Leggett, D J; McBryde, W A

    The reactions of picoline-2-aldehyde thiosemicarbazone (PATS) with silver, mercury, iron(II) and cobalt have been investigated in various environments. The compositions of the complexes have been investigated by continuous variation and molar ratio methods. Stability constants have been evaluated by means of SCOGS and a new program SQUAD. The formation constants, measured at 25 degrees and 0.10M ionic strength were as follows: Ag(PATS), logbeta(101) = 13.40; HgH(PATS), log beta(1110) = 23.6; HgH(2)(PATS)(2), log beta(1220) = 42.1; HgH(2)(PATS)(EDTA), log beta = 44.0; FeH(3)(PATS)(3), log beta(133) = 44.9; FeH(2)(PATS)(3), log beta(123) = 41.7; FeH(PATS)(3), log beta(113) = 38.4; Fe(PATS)(3), log beta(103) = 34.2. A tentative value for a cobalt complex is also suggested. A computer program, suitable for calculation of optimum conditions for a chemical analysis is also introduced and its use is illustrated for the silver-PATS-EDTA system.

  3. An animal model of human aldehyde dehydrogenase deficiency

    SciTech Connect

    Chang, C.; Mann, J.; Yoshida, A.

    1994-09-01

    The genetic deficiency of ALDH2, a major mitochondrial aldehyde dehydrogenase, is intimately related to alcohol sensitivity and the degree of predisposition to alcoholic diseases in humans. The ultimate biological role of ALDH2 can be exposed by knocking out the ALDH2 gene in an animal model. As the first step for this line of studies, we cloned and characterized the ALDH2 gene from mouse C57/6J strain which is associated with a high alcohol preference. The gene spans 26 kbp and is composed of 13 exons. Embryonic stem cells were transfected with a replacement vector which contains a partially deleted exon3, a positive selection cassette (pPgk Neo), exon 4 with an artificial stop codon, exons 5, 6, 7, and a negative selection cassette (pMCI-Tk). Genomic DNAs prepared from drug resistant clones were analyzed by polymerase chain reaction and by Southern blot analysis to distinguish random integration from homologous recombination. Out of 132 clones examined, 8 had undergone homologous recombination at one of the ALDH2 alleles. The cloned transformed embryonic stem cells with a disrupted ALDH2 allele were injected into blastocysts. Transplantation of the blastocysts into surrogate mother mice yielded chimeric mice. The role of ALDH2 in alcohol preference, alcohol sensitivity and other biological and behavioral characteristics can be elucidated by examining the heterozygous and homozygous mutant strains produced by breeding of chimeric mice.

  4. Sodium borohydride removes aldehyde inhibitors for enhancing biohydrogen fermentation.

    PubMed

    Lin, Richen; Cheng, Jun; Ding, Lingkan; Song, Wenlu; Zhou, Junhu; Cen, Kefa

    2015-12-01

    To enhance biohydrogen production from glucose and xylose in the presence of aldehyde inhibitors, reducing agent (i.e., sodium borohydride) was in situ added for effective detoxification. The detoxification efficiencies of furfural (96.7%) and 5-hydroxymethylfurfural (5-HMF, 91.7%) with 30mM NaBH4 were much higher than those of vanillin (77.3%) and syringaldehyde (69.3%). Biohydrogen fermentation was completely inhibited without detoxification, probably because of the consumption of nicotinamide adenine dinucleotide (NADH) by inhibitors reduction (R-CHO+2NADH→R-CH2OH+2NAD(+)). Addition of 30mM NaBH4 provided the reducing power necessary for inhibitors reduction (4R-CHO+NaBH4+2H2O→4R-CH2OH+NaBO2). The recovered reducing power in fermentation resulted in 99.3% recovery of the hydrogen yield and 64.6% recovery of peak production rate. Metabolite production and carbon conversion after detoxification significantly increased to 63.7mM and 81.9%, respectively.

  5. Aldehyde dehydrogenase induction in arsenic-exposed rat bladder epithelium.

    PubMed

    Huang, Ya-Chun; Yu, Hsin-Su; Chai, Chee-Yin

    2016-01-01

    Arsenic is widely distributed in the environment. Many human cancers, including urothelial carcinoma (UC), show a dose-dependent relationship with arsenic exposure in the south-west coast of Taiwan (also known as the blackfoot disease (BFD) areas). However, the molecular mechanisms of arsenic-mediated UC carcinogenesis has not yet been defined. In vivo study, the rat bladder epithelium were exposed with arsenic for 48 h. The proteins were extracted from untreated and arsenic-treated rat bladder cells and utilized two-dimensional gel electrophoresis and mass spectrometry. Selected peptides were extracted from the gel and identified by quadrupole-time of flight (Q-TOF) Ultima-Micromass spectra. The significantly difference expression of proteins in arsenic-treated groups as compared with untreated groups was confirmed by immunohistochemistry (IHC) and western blotting. We found that thirteen proteins were down-regulated and nine proteins were up-regulated in arsenic-treated rat bladder cells when compared with untreated groups. The IHC and western blotting results confirmed that aldehyde dehydrogenase (ALDH) protein was up-regulated in arsenic-treated rat bladder epithelium. Expression of ALDH protein was significantly higher in UC patients from BFD areas than those from non-BFD areas using IHC (p=0.018). In conclusion, the ALDH protein expression could be used as molecular markers for arsenic-induced transformation. PMID:26482281

  6. The participation of human hepatic P450 isoforms, flavin-containing monooxygenases and aldehyde oxidase in the biotransformation of the insecticide fenthion

    SciTech Connect

    Leoni, Claudia; Buratti, Franca M. Testai, Emanuela

    2008-12-01

    Although fenthion (FEN) is widely used as a broad spectrum insecticide on various crops in many countries, very scant data are available on its biotransformation in humans. In this study the in vitro human hepatic FEN biotransformation was characterized, identifying the relative contributions of cytochrome P450 (CYPs) and/or flavin-containing monooxygenase (FMOs) by using single c-DNA expressed human enzymes, human liver microsomes and cytosol and CYP/FMO-specific inhibitors. Two major metabolites, FEN-sulfoxide and FEN-oxon (FOX), are formed by some CYPs although at very different levels, depending on the relative CYP hepatic content. Formation of further oxidation products and the reduction of FEN-sulfoxide back to FEN by the cytosolic aldehyde oxidase enzyme were ruled out. Comparing intrinsic clearance values, FOX formation seemed to be favored and at low FEN concentrations CYP2B6 and 1A2 are mainly involved in its formation. At higher levels, a more widespread CYP involvement was evident, as in the case of FEN-sulfoxide, although a higher efficiency of CYP2C family was suggested. Hepatic FMOs were able to catalyze only sulfoxide formation, but at low FEN concentrations hepatic FEN sulfoxidation is predominantly P450-driven. Indeed, the contribution of the hepatic isoforms FMO{sub 3} and FMO{sub 5} was generally negligible, although at high FEN concentrations FMO's showed activities comparable to the active CYPs, accounting for up to 30% of total sulfoxidation. Recombinant FMO{sub 1} showed the highest efficiency with respect to CYPs and the other FMOs, but it is not expressed in the adult human liver. This suggests that FMO{sub 1}-catalysed sulfoxidation may represent the major extra-hepatic pathway of FEN biotransformation.

  7. A general and efficient aldehyde decarbonylation reaction by using a palladium catalyst.

    PubMed

    Modak, Atanu; Deb, Arghya; Patra, Tuhin; Rana, Sujoy; Maity, Soham; Maiti, Debabrata

    2012-05-01

    A facile decarbonylation reaction of aldehydes has been developed by employing Pd(OAc)(2). A wide variety of substrates are decarbonylated, without using any exogenous ligand for palladium as well as CO-scavenger.

  8. Carbon-Carbon Bond Formation and Hydrogen Production in the Ketonization of Aldehydes.

    PubMed

    Orozco, Lina M; Renz, Michael; Corma, Avelino

    2016-09-01

    Aldehydes possess relatively high chemical energy, which is the driving force for disproportionation reactions such as Cannizzaro and Tishchenko reactions. Generally, this energy is wasted if aldehydes are transformed into carboxylic acids with a sacrificial oxidant. Here, we describe a cascade reaction in which the surplus energy of the transformation is liberated as molecular hydrogen for the oxidation of heptanal to heptanoic acid by water, and the carboxylic acid is transformed into potentially industrially relevant symmetrical ketones by ketonic decarboxylation. The cascade reaction is catalyzed by monoclinic zirconium oxide (m-ZrO2 ). The reaction mechanism has been studied through cross-coupling experiments between different aldehydes and acids, and the final symmetrical ketones are formed by a reaction pathway that involves the previously formed carboxylic acids. Isotopic studies indicate that the carboxylic acid can be formed by a hydride shift from the adsorbed aldehyde on the metal oxide surface in the absence of noble metals. PMID:27539722

  9. Nanogels based on alginic aldehyde and gelatin by inverse miniemulsion technique: synthesis and characterization.

    PubMed

    Sarika, P R; Anil Kumar, P R; Raj, Deepa K; James, Nirmala Rachel

    2015-03-30

    Nanogels were developed from alginic aldehyde and gelatin by an inverse miniemulsion technique. Stable inverse miniemulsions were prepared by sonication of noncontinuous aqueous phase (mixture of alginic aldehyde and gelatin) in a continuous organic phase (Span 20 dissolved in cyclohexane). Cross-linking occurred between alginic aldehyde (AA) and gelatin (gel) in the presence of borax by Schiff's base reaction during the formation of inverse miniemulsion. The effects of surfactant (Span 20) concentration, volume of the aqueous phase and AA/gel weight ratio on the size of the alginic aldehyde-gelatin (AA-gel) nanoparticles were studied. Nanogels were characterized by DLS, FT-IR spectroscopy, TGA, SEM and TEM. DLS, TEM and SEM studies demonstrated nanosize and spherical morphology of the nanogels. Hemocompatibility and in vitro cytocompatibility analyses of the nanogels proved their nontoxicity. The results indicated the potential of the present nanogel system as a candidate for drug- and gene-delivery applications.

  10. Nanogels based on alginic aldehyde and gelatin by inverse miniemulsion technique: synthesis and characterization.

    PubMed

    Sarika, P R; Anil Kumar, P R; Raj, Deepa K; James, Nirmala Rachel

    2015-03-30

    Nanogels were developed from alginic aldehyde and gelatin by an inverse miniemulsion technique. Stable inverse miniemulsions were prepared by sonication of noncontinuous aqueous phase (mixture of alginic aldehyde and gelatin) in a continuous organic phase (Span 20 dissolved in cyclohexane). Cross-linking occurred between alginic aldehyde (AA) and gelatin (gel) in the presence of borax by Schiff's base reaction during the formation of inverse miniemulsion. The effects of surfactant (Span 20) concentration, volume of the aqueous phase and AA/gel weight ratio on the size of the alginic aldehyde-gelatin (AA-gel) nanoparticles were studied. Nanogels were characterized by DLS, FT-IR spectroscopy, TGA, SEM and TEM. DLS, TEM and SEM studies demonstrated nanosize and spherical morphology of the nanogels. Hemocompatibility and in vitro cytocompatibility analyses of the nanogels proved their nontoxicity. The results indicated the potential of the present nanogel system as a candidate for drug- and gene-delivery applications. PMID:25563951

  11. Copper catalyzed oxidative esterification of aldehydes with alkylbenzenes via cross dehydrogenative coupling.

    PubMed

    Rout, Saroj Kumar; Guin, Srimanta; Ghara, Krishna Kanta; Banerjee, Arghya; Patel, Bhisma K

    2012-08-01

    Copper(II) as the catalyst in a cross dehydrogenative coupling (CDC) reaction has been demonstrated for the synthesis of benzylic esters using aldehydes and alkylbenzenes as coupling partners. PMID:22817825

  12. Human cytosolic extracts stabilize the HIV-1 core.

    PubMed

    Fricke, Thomas; Brandariz-Nuñez, Alberto; Wang, Xiaozhao; Smith, Amos B; Diaz-Griffero, Felipe

    2013-10-01

    The stability of the HIV-1 core in the cytoplasm is crucial for productive HIV-1 infection. Mutations that stabilize or destabilize the core showed defects on HIV-1 reverse transcription and infection. We developed a novel and simple assay to measure the stability of in vitro-assembled HIV-1 CA-NC complexes. The assay allowed us to demonstrate that cytosolic extracts strongly stabilize the HIV-1 core. Interestingly, stabilization of in vitro-assembled HIV-1 CA-NC complexes is not due solely to macromolecular crowding, suggesting the presence of specific cellular factors that stabilize the HIV-1 core. By using our novel assay, we measured the abilities of different drugs, such as PF74, CAP-1, IXN-053, cyclosporine, Bi2 (also known as BI-2), and the peptide CAI, to modulate the stability of in vitro-assembled HIV-1 CA-NC complexes. Interestingly, we found that PF74 and Bi2 strongly stabilized HIV-1 CA-NC complexes. On the other hand, the peptide CAI destabilized HIV-1 CA-NC complexes. We also found that purified cyclophilin A destabilizes in vitro-assembled HIV-1 CA-NC complexes in the presence of cellular extracts in a cyclosporine-sensitive manner. In agreement with previous observations using the fate-of-the-capsid assay, we also demonstrated the ability of recombinant CPSF6 to stabilize HIV-1 CA-NC complexes. Overall, our findings suggested that cellular extracts specifically stabilize the HIV-1 core. We believe that our assay can be a powerful tool to assess HIV-1 core stability in vitro.

  13. Propionate induces the bovine cytosolic phosphoenolpyruvate carboxykinase promoter activity.

    PubMed

    Zhang, Qian; Koser, Stephanie L; Donkin, Shawn S

    2016-08-01

    Cytosolic phosphoenolpyruvate carboxykinase (PCK1) is a critical enzyme within the metabolic networks for gluconeogenesis, hepatic energy metabolism, and tricarboxylic acid cycle function, and is controlled by several transcription factors including hepatic nuclear factor 4α (HNF4α). The primary objective of the present study was to determine whether propionate regulates bovine PCK1 transcription. The second objective was to determine the action of cyclic AMP (cAMP), glucocorticoids, and insulin, hormonal cues known to modulate glucose metabolism, on bovine PCK1 transcriptional activity. The proximal promoter of the bovine PCK1 gene was ligated to a Firefly luciferase reporter and transfected into H4IIE hepatoma cells. Cells were exposed to treatments for 23 h and luciferase activity was determined in cell lysates. Activity of the PCK1 promoter was linearly induced by propionate, and maximally increased 7-fold with 2.5 mM propionate, which was not muted by 100 nM insulin. Activity of the PCK1 promoter was increased 1-fold by either 1.0 mM cAMP or 5.0µM dexamethasone, and 2.2-fold by their combination. Induction by cAMP and dexamethasone was repressed 50% by 100 nM insulin. Propionate, cAMP, and dexamethasone acted synergistically to induce the PCK1 promoter activity. Propionate-responsive regions, identified by 5' deletion analysis, were located between -1,238 and -409 bp and between -85 and +221 bp. Deletions of the core sequences of the 2 putative HNF4α sites decreased the responsiveness to propionate by approximately 40%. These data indicate that propionate regulates its own metabolism through transcriptional stimulation of the bovine PCK1 gene. This induction is mediated, in part, by the 2 putative HNF4α binding sites in the bovine PCK1 promoter. PMID:27289145

  14. Cytosolic superoxide dismutase can provide protection against Fasciola gigantica.

    PubMed

    Jaikua, Wipaphorn; Kueakhai, Pornanan; Chaithirayanon, Kulathida; Tanomrat, Rataya; Wongwairot, Sirima; Riengrojpitak, Suda; Sobhon, Prasert; Changklungmoa, Narin

    2016-10-01

    Superoxide dismutases (SOD), antioxidant metallo-enzymes, are a part of the first line of defense in the trematode parasites which act as the chief scavengers for reactive oxygen species (ROS). A recombinant Fasciola gigantica cytosolic SOD (FgSOD) was expressed in Escherichia coli BL21 (DE3) and used for immunizing rabbits to obtain polyclonal antibodies (anti-rFgSOD). This rabbit anti-rFgSOD reacted with the native FgSOD at a molecular weight of 17.5kDa. The FgSOD protein was expressed at high level in parenchyma, caecal epithelium and egg of the parasite. The rFgSOD reacted with antisera from rabbits infected with F. gigantica metacercariae collected at 2, 5, and 7 weeks after infection, and reacted with sera of infected mice. Anti-rFgSOD exhibited cross reactivity with the other parasites' antigens, including Eurytrema pancreaticum, Cotylophoron cotylophorum, Fischoederius cobboldi, Gastrothylax crumenifer, Paramphistomum cervi, and Setaria labiato papillosa. A vaccination was performed in imprinting control region (ICR) mice by subcutaneous injection with 50μg of rFgSOD combined with Freund's adjuvant. At 2 weeks after the second boost, mice were infected with 15 metacercariae by oral route. IgG1 and IgG2a in the immune sera were determined to indicate Th2 and Th1 immune responses. It was found that the parasite burden was reduced by 45%, and both IgG1 and IgG2a levels showed correlation with the numbers of worm recoveries. PMID:27338185

  15. Substrate specificity and catalytic efficiency of aldo-keto reductases with phospholipid aldehydes.

    PubMed

    Spite, Matthew; Baba, Shahid P; Ahmed, Yonis; Barski, Oleg A; Nijhawan, Kanchan; Petrash, J Mark; Bhatnagar, Aruni; Srivastava, Sanjay

    2007-07-01

    Phospholipid oxidation generates several bioactive aldehydes that remain esterified to the glycerol backbone ('core' aldehydes). These aldehydes induce endothelial cells to produce monocyte chemotactic factors and enhance monocyte-endothelium adhesion. They also serve as ligands of scavenger receptors for the uptake of oxidized lipoproteins or apoptotic cells. The biochemical pathways involved in phospholipid aldehyde metabolism, however, remain largely unknown. In the present study, we have examined the efficacy of the three mammalian AKR (aldo-keto reductase) families in catalysing the reduction of phospholipid aldehydes. The model phospholipid aldehyde POVPC [1-palmitoyl-2-(5-oxovaleroyl)-sn-glycero-3-phosphocholine] was efficiently reduced by members of the AKR1, but not by the AKR6 or the ARK7 family. In the AKR1 family, POVPC reductase activity was limited to AKR1A and B. No significant activity was observed with AKR1C enzymes. Among the active proteins, human AR (aldose reductase) (AKR1B1) showed the highest catalytic activity. The catalytic efficiency of human small intestinal AR (AKR1B10) was comparable with the murine AKR1B proteins 1B3 and 1B8. Among the murine proteins AKR1A4 and AKR1B7 showed appreciably lower catalytic activity as compared with 1B3 and 1B8. The human AKRs, 1B1 and 1B10, and the murine proteins, 1B3 and 1B8, also reduced C-7 and C-9 sn-2 aldehydes as well as POVPE [1-palmitoyl-2-(5-oxovaleroyl)-sn-glycero-3-phosphoethanolamine]. AKR1A4, B1, B7 and B8 catalysed the reduction of aldehydes generated in oxidized C(16:0-20:4) phosphatidylcholine with acyl, plasmenyl or alkyl linkage at the sn-1 position or C(16:0-20:4) phosphatidylglycerol or phosphatidic acid. AKR1B1 displayed the highest activity with phosphatidic acids; AKR1A4 was more efficient with long-chain aldehydes such as 5-hydroxy-8-oxo-6-octenoyl derivatives, whereas AKR1B8 preferred phosphatidylglycerol. These results suggest that proteins of the AKR1A and B families are

  16. JWH-018 ω-OH, a shared hydroxy metabolite of the two synthetic cannabinoids JWH-018 and AM-2201, undergoes oxidation by alcohol dehydrogenase and aldehyde dehydrogenase enzymes in vitro forming the carboxylic acid metabolite.

    PubMed

    Holm, Niels Bjerre; Noble, Carolina; Linnet, Kristian

    2016-09-30

    Synthetic cannabinoids are new psychoactive substances (NPS) acting as agonists at the cannabinoid receptors. The aminoalkylindole-type synthetic cannabinoid naphthalen-1-yl-(1-pentylindol-3-yl)methanone (JWH-018) was among the first to appear on the illicit drug market and its metabolism has been extensively investigated. The N-pentyl side chain is a major site of human cytochrome P450 (CYP)-mediated oxidative metabolism, and the ω-carboxylic acid metabolite appears to be a major in vivo human urinary metabolite. This metabolite is, however, not formed to any significant extent in human liver microsomal (HLM) incubations raising the possibility that the discrepancy is due to involvement of cytosolic enzymes. Here we demonstrate in incubations with human liver cytosol (HLC), that JWH-018 ω-OH, but not the JWH-018 parent compound, is a substrate for nicotinamide adenine dinucleotide (NAD(+))-dependent alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) enzymes. The sole end-product identified in HLC was the JWH-018 ω-COOH metabolite, while trapping tests with methoxyamine proved the presence of the aldehyde intermediate. ADH/ALDH and UDP-glucuronosyl-transferases (UGT) enzymes may therefore both act on the JWH-018 ω-OH substrate. Finally, we note that for [1-(5-fluoropentyl)indol-3-yl]-naphthalen-1-yl-methanone (AM-2201), the ω-fluorinated analog of JWH-018, a high amount of JWH-018 ω-OH was formed in HLM incubated without NADPH, suggesting that the oxidative defluorination is efficiently catalyzed by non-CYP enzyme(s). The pathway presented here may therefore be especially important for N-(5-fluoropentyl) substituted synthetic cannabinoids, because the oxidative defluorination can occur even if the CYP-mediated metabolism preferentially takes place on other parts of the molecule than the N-alkyl side chain. Controlled clinical studies in humans are ultimately required to demonstrate the in vivo importance of the oxidation pathway presented here

  17. JWH-018 ω-OH, a shared hydroxy metabolite of the two synthetic cannabinoids JWH-018 and AM-2201, undergoes oxidation by alcohol dehydrogenase and aldehyde dehydrogenase enzymes in vitro forming the carboxylic acid metabolite.

    PubMed

    Holm, Niels Bjerre; Noble, Carolina; Linnet, Kristian

    2016-09-30

    Synthetic cannabinoids are new psychoactive substances (NPS) acting as agonists at the cannabinoid receptors. The aminoalkylindole-type synthetic cannabinoid naphthalen-1-yl-(1-pentylindol-3-yl)methanone (JWH-018) was among the first to appear on the illicit drug market and its metabolism has been extensively investigated. The N-pentyl side chain is a major site of human cytochrome P450 (CYP)-mediated oxidative metabolism, and the ω-carboxylic acid metabolite appears to be a major in vivo human urinary metabolite. This metabolite is, however, not formed to any significant extent in human liver microsomal (HLM) incubations raising the possibility that the discrepancy is due to involvement of cytosolic enzymes. Here we demonstrate in incubations with human liver cytosol (HLC), that JWH-018 ω-OH, but not the JWH-018 parent compound, is a substrate for nicotinamide adenine dinucleotide (NAD(+))-dependent alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) enzymes. The sole end-product identified in HLC was the JWH-018 ω-COOH metabolite, while trapping tests with methoxyamine proved the presence of the aldehyde intermediate. ADH/ALDH and UDP-glucuronosyl-transferases (UGT) enzymes may therefore both act on the JWH-018 ω-OH substrate. Finally, we note that for [1-(5-fluoropentyl)indol-3-yl]-naphthalen-1-yl-methanone (AM-2201), the ω-fluorinated analog of JWH-018, a high amount of JWH-018 ω-OH was formed in HLM incubated without NADPH, suggesting that the oxidative defluorination is efficiently catalyzed by non-CYP enzyme(s). The pathway presented here may therefore be especially important for N-(5-fluoropentyl) substituted synthetic cannabinoids, because the oxidative defluorination can occur even if the CYP-mediated metabolism preferentially takes place on other parts of the molecule than the N-alkyl side chain. Controlled clinical studies in humans are ultimately required to demonstrate the in vivo importance of the oxidation pathway presented here.

  18. Photoredox Activation for the Direct β-Arylation of Ketones and Aldehydes

    PubMed Central

    Pirnot, Michael T.; Rankic, Danica A.; Martin, David B. C.; MacMillan, David W. C.

    2013-01-01

    The direct β-activation of saturated aldehydes and ketones has long been an elusive transformation. We found that photoredox catalysis in combination with organocatalysis can lead to the transient generation of 5π-electron β-enaminyl radicals from ketones and aldehydes that rapidly couple with cyano-substituted aryl rings at the carbonyl β-position. This mode of activation is suitable for a broad range of carbonyl β-functionalization reactions and is amenable to enantioselective catalysis. PMID:23539600

  19. Metal-free oxidative decarbonylative coupling of aromatic aldehydes with arenes: direct access to biaryls.

    PubMed

    Tang, Ren-Jin; He, Qing; Yang, Luo

    2015-04-01

    A metal-free oxidative decarbonylative coupling of aromatic aldehydes with electron-rich or electron-deficient arenes to produce biaryl compounds was developed. This novel coupling was proposed to proceed via a non-chain radical homolytic aromatic substitution (HAS) type mechanism, based on the substrate scope, ortho-regioselectivity, radical trapping experiments and DFT calculation studies. With the ready availability of aromatic aldehydes and arenes, metal-free conditions should make this coupling attractive for the biaryl synthesis.

  20. Analysis of a panel of rapidly growing mycobacteria for resistance to aldehyde-based disinfectants.

    PubMed

    De Groote, Mary Ann; Gibbs, Sara; de Moura, Vinicius Calado Nogueira; Burgess, Winona; Richardson, Kris; Kasperbauer, Shannon; Madinger, Nancy; Jackson, Mary

    2014-08-01

    After several accounts across the globe of mycobacteria outbreaks associated with medical procedures and aldehyde disinfectants resistance, we undertook an analysis of mycobacteria isolated from patients seen in a hospital in the United States between 1994 and 2008 to determine prevalence of resistance to aldehyde-based disinfectants. Out of the 117 clinical isolates screened, 6 isolates belonging to the emerging Mycobacterium abscessus group were found to display significant levels of resistance to glutaraldehyde and ortho-phthalaldehyde.

  1. Garner’s aldehyde as a versatile intermediate in the synthesis of enantiopure natural products

    PubMed Central

    Passiniemi, Mikko

    2013-01-01

    Summary Since its introduction to the synthetic community in 1984, Garner’s aldehyde has gained substantial attention as a chiral intermediate for the synthesis of numerous amino alcohol derivatives. This review presents some of the most successful carbon chain elongation reactions, namely carbonyl alkylations and olefinations. The literature is reviewed with particular attention on understanding how to avoid the deleterious epimerization of the existing stereocenter in Garner’s aldehyde. PMID:24367429

  2. The use of tomato aminoaldehyde dehydrogenase 1 for the detection of aldehydes in fruit distillates.

    PubMed

    Frömmel, Jan; Tarkowski, Petr; Kopečný, David; Šebela, Marek

    2016-09-25

    Plant NAD(+)-dependent aminoaldehyde dehydrogenases (AMADHs, EC 1.2.1.19) belong to the family 10 of aldehyde dehydrogenases. They participate in the metabolism of polyamines or osmoprotectants. The enzymes are characterized by their broad substrate specificity covering ω-aminoaldehydes, aliphatic and aromatic aldehydes as well as nitrogen-containing heterocyclic aldehydes. The isoenzyme 1 from tomato (Solanum lycopersicum; SlAMADH1) oxidizes aliphatic aldehydes very efficiently and converts also furfural, its derivatives or benzaldehyde, which are present at low concentrations in alcoholic distillates such as fruit brandy. In this work, SlAMADH1 was examined as a bioanalytical tool for their detection. These aldehydes arise from fermentation processes or thermal degradation of sugars and their presence is related to health complications after consumption including nausea, emesis, sweating, decrease in blood pressure, hangover headache, among others. Sixteen samples of slivovitz (plum brandy) from local producers in Moravia, Czech Republic, were analyzed for their aldehyde content using a spectrophotometric activity assay with SlAMADH1. In all cases, there were oxidative responses observed when monitoring NADH production in the enzymatic reaction. Aldehydes in the distillate samples were also subjected to a standard determination using reversed-phase HPLC with spectrophotometric and tandem mass spectrometric detection after a derivatization with 2,4-dinitrophenylhydrazine. Results obtained by both methods were found to correlate well for a majority of the analyzed samples. The possible applicability of SlAMADH1 for the evaluation of aldehyde content in food and beverages has now been demonstrated. PMID:26703808

  3. Aldehyde-Resistant Mycobacteria Associated with the Use of Endoscope Reprocessing Systems

    PubMed Central

    Fisher, Christopher W.; Fiorello, Anthony; Shaffer, Diana; Jackson, Mary

    2012-01-01

    Bacteria can develop resistance to antibiotics, but less is known about their ability to increase resistance to chemical disinfectants. This study randomly sampled three AERs in the USA using aldehydes for endoscope disinfection. Bacterial contamination was found post-disinfection in all AERs and some mycobacteria isolated demonstrated significant resistance to glutaraldehyde and OPA disinfectants. Bacteria can survive aldehyde-based disinfection and may pose a cross-contamination risk to patients. PMID:22325730

  4. Elucidation of the Biotransformation Pathways of a Galnac3-conjugated Antisense Oligonucleotide in Rats and Monkeys

    PubMed Central

    Shemesh, Colby S; Yu, Rosie Z; Gaus, Hans J; Greenlee, Sarah; Post, Noah; Schmidt, Karsten; Migawa, Michael T; Seth, Punit P; Zanardi, Thomas A; Prakash, Thazha P; Swayze, Eric E; Henry, Scott P; Wang, Yanfeng

    2016-01-01

    Triantennary N-acetyl galactosamine (GalNAc3) is a high-affinity ligand for hepatocyte-specific asialoglycoprotein receptors. Conjugation with GalNAc3 via a trishexylamino (THA)-C6 cluster significantly enhances antisense oligonucleotide (ASO) potency. Herein, the biotransformation, disposition, and elimination of the THA cluster of ION-681257, a GalNAc3-conjugated ASO currently in clinical development, are investigated in rats and monkey. Rats were administered a single subcutaneous dose of 3H-radiolabeled (3H placed in THA) or nonradiolabeled ION-681257. Mass balance included radiometric profiling and metabolite fractionation with characterization by mass spectrometry. GalNAc3-conjugated ASOs were extensively distributed into liver. The THA-C6 triantenerrary GalNAc3 conjugate at the 5′-end of the ASO was rapidly metabolized and excreted with 25.67 ± 1.635% and 71.66 ± 4.17% of radioactivity recovered in urine and feces within 48 hours postdose. Unchanged drug, short-mer ASOs, and linker metabolites were detected in urine. Collectively, 14 novel linker associated metabolites were discovered including oxidation at each branching arm, initially by monooxidation at the β-position followed by dioxidation at the α-arm, and lastly, tri and tetra oxidations on the two remaining β-arms. Metabolites in bile and feces were identical to urine except for oxidized linear and cyclic linker metabolites. Enzymatic reaction phenotyping confirmed involvement of N-acetyl-β-glucosaminidase, deoxyribonuclease II, alkaline phosphatase, and alcohol + aldehyde dehydrogenases on the complex metabolism pathway for THA supplementing in vivo findings. Lastly, excreta from monkeys treated with ION-681257 revealed the identical series as observed in rat. In summary, our findings provide an improved understanding of GalNAc3-conjugated-ASO metabolism pathways which facilitate similar development programs. PMID:27164023

  5. Elucidation of the Biotransformation Pathways of a Galnac3-conjugated Antisense Oligonucleotide in Rats and Monkeys.

    PubMed

    Shemesh, Colby S; Yu, Rosie Z; Gaus, Hans J; Greenlee, Sarah; Post, Noah; Schmidt, Karsten; Migawa, Michael T; Seth, Punit P; Zanardi, Thomas A; Prakash, Thazha P; Swayze, Eric E; Henry, Scott P; Wang, Yanfeng

    2016-01-01

    Triantennary N-acetyl galactosamine (GalNAc3) is a high-affinity ligand for hepatocyte-specific asialoglycoprotein receptors. Conjugation with GalNAc3 via a trishexylamino (THA)-C6 cluster significantly enhances antisense oligonucleotide (ASO) potency. Herein, the biotransformation, disposition, and elimination of the THA cluster of ION-681257, a GalNAc3-conjugated ASO currently in clinical development, are investigated in rats and monkey. Rats were administered a single subcutaneous dose of (3)H-radiolabeled ((3)H placed in THA) or nonradiolabeled ION-681257. Mass balance included radiometric profiling and metabolite fractionation with characterization by mass spectrometry. GalNAc3-conjugated ASOs were extensively distributed into liver. The THA-C6 triantenerrary GalNAc3 conjugate at the 5'-end of the ASO was rapidly metabolized and excreted with 25.67 ± 1.635% and 71.66 ± 4.17% of radioactivity recovered in urine and feces within 48 hours postdose. Unchanged drug, short-mer ASOs, and linker metabolites were detected in urine. Collectively, 14 novel linker associated metabolites were discovered including oxidation at each branching arm, initially by monooxidation at the β-position followed by dioxidation at the α-arm, and lastly, tri and tetra oxidations on the two remaining β-arms. Metabolites in bile and feces were identical to urine except for oxidized linear and cyclic linker metabolites. Enzymatic reaction phenotyping confirmed involvement of N-acetyl-β-glucosaminidase, deoxyribonuclease II, alkaline phosphatase, and alcohol + aldehyde dehydrogenases on the complex metabolism pathway for THA supplementing in vivo findings. Lastly, excreta from monkeys treated with ION-681257 revealed the identical series as observed in rat. In summary, our findings provide an improved understanding of GalNAc3-conjugated-ASO metabolism pathways which facilitate similar development programs. PMID:27164023

  6. Orderings for conjugate gradient preconditionings

    NASA Technical Reports Server (NTRS)

    Ortega, James M.

    1991-01-01

    The effect of orderings on the rate of convergence of the conjugate gradient method with SSOR or incomplete Cholesky preconditioning is examined. Some results also are presented that help to explain why red/black ordering gives an inferior rate of convergence.

  7. Enhanced photophysics of conjugated polymers

    DOEpatents

    Chen, Liaohai

    2007-06-12

    A particulate fluorescent conjugated polymer surfactant complex and method of making and using same. The particles are between about 15 and about 50 nm and when formed from a lipsome surfactant have a charge density similar to DNA and are strongly absorbed by cancer cells.

  8. KAHA ligations that form aspartyl aldehyde residues as synthetic handles for protein modification and purification.

    PubMed

    Murar, Claudia E; Thuaud, Frédéric; Bode, Jeffrey W

    2014-12-31

    Aldehydes are widely recognized as valuable synthetic handles for the chemoselective manipulation of peptides and proteins. In this report, we show that peptides and small proteins containing the aspartic acid semialdehyde (Asa) side chain can be easily prepared by a chemoselective amide-forming ligation that results in the formation of the Asa residue at the ligation site. This strategy employs the α-ketoacid-hydroxylamine (KAHA) ligation in combination with a new isoxazolidine monomer that forms a side-chain aldehyde upon ligation. This monomer is easily prepared on a preparative scale by a catalytic, enantioselective approach and is readily introduced onto the N-terminus of a peptide segment by solid phase peptide synthesis. The ligated product can be further functionalized by bioorthogonal reactions between the aldehyde residue and alkoxyamines or hydrazides. We demonstrated that glucagon aldehyde, an unprotected 29-mer peptide prepared by KAHA ligation, can be site specifically and chemoselectively modified with biotin, dyes, aliphatic oximes, and hydroxylamines. We further describe a simple and high recovery one-step purification process based on the capture of a 29-mer glucagon aldehyde and a 76-mer ubiquitin aldehyde by an alkoxyamine-functionalized polyethylene glycol resin. The peptide or protein was released from the resin by addition of a hydroxylamine to provide the corresponding oximes.

  9. Aldose and aldehyde reductases : structure-function studies on the coenzyme and inhibitor-binding sites.

    SciTech Connect

    El-Kabbani, O.; Old, S. E.; Ginell, S. L.; Carper, D. A.; Biosciences Division; Monash Univ.; NIH

    1999-09-03

    PURPOSE: To identify the structural features responsible for the differences in coenzyme and inhibitor specificities of aldose and aldehyde reductases. METHODS: The crystal structure of porcine aldehyde reductase in complex with NADPH and the aldose reductase inhibitor sorbinil was determined. The contribution of each amino acid lining the coenzyme-binding site to the binding of NADPH was calculated using the Discover package. In human aldose reductase, the role of the non-conserved Pro 216 (Ser in aldehyde reductase) in the binding of coenzyme was examined by site-directed mutagenesis. RESULTS: Sorbinil binds to the active site of aldehyde reductase and is hydrogen-bonded to Trp 22, Tyr 50, His 113, and the non-conserved Arg 312. Unlike tolrestat, the binding of sorbinil does not induce a change in the side chain conformation of Arg 312. Mutation of Pro 216 to Ser in aldose reductase makes the binding of coenzyme more similar to that of aldehyde reductase. CONCLUSIONS: The participation of non-conserved active site residues in the binding of inhibitors and the differences in the structural changes required for the binding to occur are responsible for the differences in the potency of inhibition of aldose and aldehyde reductases. We report that the non-conserved Pro 216 in aldose reductase contributes to the tight binding of NADPH.

  10. Brain and Liver Headspace Aldehyde Concentration Following Dietary Supplementation with n-3 Polyunsaturated Fatty Acids.

    PubMed

    Ross, Brian M; Babay, Slim; Malik, Imran

    2015-11-01

    Reactive oxygen species react with unsaturated fatty acids to form a variety of metabolites including aldehydes. Many aldehydes are volatile enough to be detected in headspace gases of blood or cultured cells and in exhaled breath, in particular propanal and hexanal which are derived from omega-3 and omega-6 polyunsaturated fatty acids, respectively. Aldehydes are therefore potential non-invasive biomarkers of oxidative stress and of various diseases in which oxidative stress is thought to play a role including cancer, cardiovascular disease and diabetes. It is unclear, however, how changes in the abundance of the fatty acid precursors, for example by altered dietary intake, affect aldehyde concentrations. We therefore fed male Wistar rats diets supplemented with either palm oil or a combination of palm oil plus an n-3 fatty acid (alpha-linolenic, eicosapentaenoic, or docosahexaenoic acids) for 4 weeks. Fatty acid analysis revealed large changes in the abundance of both n-3 and n-6 fatty acids in the liver with smaller changes observed in the brain. Despite the altered fatty acid abundance, headspace concentrations of C1-C8 aldehydes, and tissue concentrations of thiobarbituric acid reactive substances, did not differ between the 4 dietary groups. Our data suggest that tissue aldehyde concentrations are independent of fatty acid abundance, and further support their use as volatile biomarkers of oxidative stress.

  11. Introduction of aldehyde vs. carboxylic groups to cellulose nanofibers using laccase/TEMPO mediated oxidation.

    PubMed

    Jaušovec, Darja; Vogrinčič, Robert; Kokol, Vanja

    2015-02-13

    The chemo-enzymatic modification of cellulose nanofibers (CNFs) using laccase as biocatalysts and TEMPO or 4-Amino-TEMPO as mediators under mild aqueous conditions (pH 5, 30 °C) has been investigated to introduce surface active aldehyde groups. 4-Amino TEMPO turned out to be kinetically 0.5-times (50%) more active mediator, resulting to oxoammonium cation intermediacy generated and its in situ regeneration during the modification of CNFs. Accordingly, beside of around 750 mmol/kg terminally-located aldehydes, originated during CNFs isolation, the reaction resulted to about 140% increase of C6-located aldehydes at optimal conditions, without reducing CNFs crystallinity. While only the C6-aldehydes were wholly transformed into the carboxyls after additional post-treatment using NaOH according to the Cannizzaro reaction, the post-oxidation with air-oxygen in EtOH/water medium or NaClO2 resulted to no- or very small amounts of carboxyls created, respectively, at a simultaneous loss of all C6- and some terminal-aldehydes in the latter due to the formation of highly-resistant hemiacetal covalent linkages with available cellulose hydroxyls. The results indicated a new way of preparing and stabilizing highly reactive C6-aldehydes on cellulose, and their exploitation in the development of new nanocellulose-based materials.

  12. Release and Formation of Oxidation-Related Aldehydes during Wine Oxidation.

    PubMed

    Bueno, Mónica; Carrascón, Vanesa; Ferreira, Vicente

    2016-01-27

    Twenty-four Spanish wines were subjected to five consecutive cycles of air saturation at 25 °C. Free and bound forms of carbonyls were measured in the initial samples and after each saturation. Nonoxidized commercial wines contain important and sensory relevant amounts of oxidation-related carbonyls under the form of odorless bound forms. Models relating the contents in total aldehydes to the wine chemical composition suggest that fermentation can be a major origin for Strecker aldehydes: methional, phenylacetaldehyde, isobutyraldehyde, 2-methylbutanal, and isovaleraldehyde. Bound forms are further cleaved, releasing free aldehydes during the first steps of wine oxidation, as a consequence of equilibrium shifts caused by the depletion of SO2. At low levels of free SO2, de novo formation and aldehyde degradation are both observed. The relative importance of these phenomena depends on both the aldehyde and the wine. Models relating aldehyde formation rates to wine chemical composition suggest that amino acids are in most cases the most important precursors for de novo formation.

  13. [Fatty aldehydes of the plasmalogenic form of phosphatidylethanolamine in the vertebrate brain].

    PubMed

    Kruglova, E E

    1979-01-01

    Studies have been made on the composition of fatty aldehydes of plasmalogen form of ethanolamine phospholipid in the brain of 28 fish species (13 cartilaginous and 15 teleost species, exhibiting different level of organization of the nervous system, marine and freshwater, dwelling in different habitats), as well as in the brain of other vertebrates. It was found that in all primitive species of cartilaginous fish high degree of unsaturation of fatty aldehydes is observed; in higher species the degree of unsaturation is much lower. The highest degree of unsaturation of fatty aldehydes was demonstrated for abyssal species of cartilaginous and teleost fishes. In warm-water species which dwell in the upper layers, unlike all other fishes investigated, almost all fatty aldehydes are saturated. The ratio of unsaturated and saturated fatty aldehydes in fish brain depends on the entity of phylogenetic and ecological factors. Studies on other vertebrates show that in warm-blooded animals saturated fatty aldehydes predominate, whereas in cold-blooded-unsaturated ones are more abundant. PMID:314210

  14. Effect of selected aldehydes on the growth and fermentation of ethanologenic Escherichia coli

    SciTech Connect

    Zaldivar, J.; Ingram, L.O.; Martinez, A. |

    1999-10-05

    Bioethanol production from lignocellulosic raw-materials requires the hydrolysis of carbohydrate polymers into a fermentable syrup. During the hydrolysis of hemicellulose with dilute acid, a variety of toxic compounds are produced such as soluble aromatic aldehydes from lignin and furfural from pentose destruction. In this study, the authors have investigated the toxicity of representative aldehydes (furfural, 5-hydroxymethlyfurfural, 4-hydroxybenzaldehyde, syringaldehyde, and vanillin) as inhibitors of growth and ethanol production by ethanologenic derivatives of Escherichia coli B (strains K011 and LY01). Aromatic aldyhydes were at least twice as toxic as furfural of 5-hydroxymethylfurfural on a weight basis. The toxicities of all aldehydes (and ethanol) except furfural were additive when tested in binary combinations. In all cases, combinations with furfural were unexpectedly toxic. Although the potency of these aldehydes was directly related to hydrophobicity indicating a hydrophobic site of action, none caused sufficient membrane damage to allow the leakage of intracellular magnesium even when present at sixfold the concentrations required for growth inhibition. Of the aldehydes tested, only furfural strongly inhibited ethanol production in vitro. A comparison with published results for other microorganisms indicates that LY01 is equivalent or more resistant than other biocatalysts to the aldehydes examined in this study.

  15. Accurate determination of aldehydes in amine catalysts or amines by 2,4-dinitrophenylhydrazine derivatization.

    PubMed

    Barman, Bhajendra N

    2014-01-31

    Carbonyl compounds, specifically aldehydes, present in amine catalysts or amines are determined by reversed-phase liquid chromatography using ultraviolet detection of their corresponding 2,4-dinitrophenylhydrazones. The primary focus has been to establish optimum conditions for determining aldehydes accurately because these add exposure concerns when the amine catalysts are used to manufacture polyurethane products. Concentrations of aldehydes determined by this method are found to vary with the pH of the aqueous amine solution and the derivatization time, the latter being problematic when the derivatization reaction proceeds slowly and not to completion in neutral and basic media. Accurate determination of aldehydes in amines through derivatization can be carried out at an effective solution pH of about 2 and with derivatization time of 20min. Hydrochloric acid has been used for neutralization of an amine. For complete derivatization, it is essential to protonate all nitrogen atoms in the amine. An approach for the determination of an adequate amount of acid needed for complete derivatization has been described. Several 0.2M buffer solutions varying in pH from 4 to 8 have also been used to make amine solutions for carrying out derivatization of aldehydes. These solutions have effective pHs of 10 or higher and provide much lower aldehyde concentrations compared to their true values. Mechanisms for the formation of 2,4-dinitrophenylhydrazones in both acidic and basic media are discussed. PMID:24411140

  16. Stereoselective synthesis of densely functionalized pyrrolidin-2-ones by a conjugate addition/nitro-Mannich/lactamization reaction.

    PubMed

    Anderson, James C; Horsfall, Lisa R; Kalogirou, Andreas S; Mills, Matthew R; Stepney, Gregory J; Tizzard, Graham J

    2012-07-20

    Copper-catalyzed conjugate addition of diorgano zinc reagents to nitroacrylate 1 followed by a subsequent nitro-Mannich reaction and in situ lactamization leads to an efficient one-pot synthesis of 1,3,5-trisubstituted 4-nitropyrrolidin-2-ones (5). The versatility of the reaction is shown for a wide range of N-p-(methoxy)phenyl protected aldimines 3 derived from alkyl, aryl, and heteroaryl aldehydes. The densely functionalized pyrrolidin-2-ones 5 are isolated as single diastereoisomers (40 examples, 33-84% yield). An enantioselective copper-catalyzed conjugate addition of diethylzinc led to highly crystalline products that could be recrystallized to enantiopurity in high yield. A range of successful chemoselective transformations were investigated, which widens the applicability of the pyrrolidn-2-ones as stereochemically pure building blocks for further organic synthesis. PMID:22708711

  17. Bacteriophytochromes control conjugation in Agrobacterium fabrum.

    PubMed

    Bai, Yingnan; Rottwinkel, Gregor; Feng, Juan; Liu, Yiyao; Lamparter, Tilman

    2016-08-01

    Bacterial conjugation, the transfer of single stranded plasmid DNA from donor to recipient cell, is mediated through the type IV secretion system. We performed conjugation assays using a transmissible artificial plasmid as reporter. With this assay, conjugation in Agrobacterium fabrum was modulated by the phytochromes Agp1 and Agp2, photoreceptors that are most sensitive in the red region of visible light. In conjugation studies with wild-type donor cells carrying a pBIN-GUSINT plasmid as reporter that lacked the Ti (tumor inducing) plasmid, no conjugation was observed. When either agp1(-) or agp2(-) knockout donor strains were used, plasmid DNA was delivered to the recipient, indicating that both phytochromes suppress conjugation in the wild type donor. In the recipient strains, the loss of Agp1 or Agp2 led to diminished conjugation. When wild type cells with Ti plasmid and pBIN-GUS reporter plasmid were used as donor, a high rate of conjugation was observed. The DNA transfer was down regulated by red or far-red light by a factor of 3.5. With agp1(-) or agp2(-) knockout donor cells, conjugation in the dark was about 10 times lower than with the wild type donor, and with the double knockout donor no conjugation was observed. These results imply that the phytochrome system has evolved to inhibit conjugation in the light. The decrease of conjugation under different temperature correlated with the decrease of phytochrome autophosphorylation. PMID:27261700

  18. In vitro glutathione conjugation of methyl iodide in rat, rabbit, and human blood and tissues.

    PubMed

    Poet, Torka S; Wu, Hong; Corley, Richard A; Thrall, Karla D

    2009-05-01

    Methyl iodide (MeI) is an intermediate in the manufacture of some pesticides and pharmaceuticals, and is under review for US registration as a non-ozone depleting alternative for methyl bromide for pre-plant soil fumigation. MeI is primarily metabolized via conjugation with glutathione (GSH), with further metabolism to S-methyl cysteine and methanethiol. To facilitate extrapolations of animal pharmacokinetic data to humans, rate constants for the GSH metabolism of MeI were determined in cytosols prepared from the liver and kidneys of rats, human donors, female rabbits, and rabbit fetuses, from rabbit olfactory and respiratory epithelium, and from rabbit and rat blood using a headspace vial equilibration technique and two-compartment mathematical model. MeI was metabolized in liver and kidney from adults of all three species, but metabolism was not detectable in fetal rabbit kidney. Maximal metabolic rates (V(max)) were similar in liver from rat and human donors (approximately 40 and 47 nmol/min/mg, respectively) whereas the V(max) rates in kidney cytosols varied approximately three-fold between the three species. No difference was observed in the loss of MeI from active and inactive whole blood from either rats or rabbits. The metabolism in olfactory and respiratory epithelial cytosol had Michaelis-Menten constant (K(m)) values that were several times higher than for any other tissue, suggesting essentially first-order metabolism in the nose. The metabolism of MeI in human liver cytosol prepared from five individual donors indicated two potential populations, one high affinity/low capacity and one with a lower affinity but higher capacity. PMID:19519152

  19. Listeria monocytogenes triggers AIM2-mediated pyroptosis upon infrequent bacteriolysis in the macrophage cytosol.

    PubMed

    Sauer, John-Demian; Witte, Chelsea E; Zemansky, Jason; Hanson, Bill; Lauer, Peter; Portnoy, Daniel A

    2010-05-20

    A host defense strategy against pathogens is the induction of cell death, thereby eliminating the pathogen's intracellular niche. Pyroptosis, one such form of cell death, is dependent on inflammasome activation. In a genetic screen to identify Listeria monocytogenes mutants that induced altered levels of host cell death, we identified a mutation in lmo2473 that caused hyperstimulation of IL-1beta secretion and pyroptosis following bacteriolysis in the macrophage cytosol. In addition, strains engineered to lyse in the cytosol by expression of both bacteriophage holin and lysin or induced to lyse by treatment with ampicillin stimulated pyroptosis. Pyroptosis was independent of the Nlrp3 and Nlrc4 inflammasome receptors but dependent on the inflammasome adaptor ASC and the cytosolic DNA sensor AIM2. Importantly, wild-type L. monocytogenes were also found to lyse, albeit at low levels, and trigger AIM2-dependent pyroptosis. These data suggested that pyroptosis is triggered by bacterial DNA released during cytosolic lysis.

  20. Live-cell observation of cytosolic HIV-1 assembly onset reveals RNA-interacting Gag oligomers

    PubMed Central

    Hendrix, Jelle; Baumgärtel, Viola; Schrimpf, Waldemar; Ivanchenko, Sergey; Digman, Michelle A.; Gratton, Enrico; Kräusslich, Hans-Georg; Müller, Barbara

    2015-01-01

    Assembly of the Gag polyprotein into new viral particles in infected cells is a crucial step in the retroviral replication cycle. Currently, little is known about the onset of assembly in the cytosol. In this paper, we analyzed the cytosolic HIV-1 Gag fraction in real time in live cells using advanced fluctuation imaging methods and thereby provide detailed insights into the complex relationship between cytosolic Gag mobility, stoichiometry, and interactions. We show that Gag diffuses as a monomer on the subsecond timescale with severely reduced mobility. Reduction of mobility is associated with basic residues in its nucleocapsid (NC) domain, whereas capsid (CA) and matrix (MA) domains do not contribute significantly. Strikingly, another diffusive Gag species was observed on the seconds timescale that oligomerized in a concentration-dependent manner. Both NC- and CA-mediated interactions strongly assist this process. Our results reveal potential nucleation steps of cytosolic Gag fractions before membrane-assisted Gag assembly. PMID:26283800

  1. Carbonic anhydrase inhibitors. Inhibition of human cytosolic isoforms I and II with (reduced) Schiff's bases incorporating sulfonamide, carboxylate and carboxymethyl moieties.

    PubMed

    Nasr, Gihane; Cristian, Alina; Barboiu, Mihail; Vullo, Daniella; Winum, Jean-Yves; Supuran, Claudiu T

    2014-05-15

    A library of Schiff bases was synthesized by condensation of aromatic amines incorporating sulfonamide, carboxylic acid or carboxymethyl functionalities as Zn(2+)-binding groups, with aromatic aldehydes incorporating tert-butyl, hydroxy and/or methoxy groups. The corresponding amines were thereafter obtained by reduction of the imines. These compounds were assayed for the inhibition of two cytosolic human carbonic anhydrase (hCA, EC 4.2.1.1) isoenzymes, hCA I and II. The Ki values of the Schiff bases were in the range of 7.0-21,400nM against hCA II and of 52-8600nM against hCA I, respectively. The corresponding amines showed Ki values in the range of 8.6nM-5.3μM against hCA II, and of 18.7-251nM against hCA I, respectively. Unlike the imines, the reduced Schiff bases are stable to hydrolysis and several low-nanomolar inhibitors were detected, most of them incorporating sulfonamide groups. Some carboxylates also showed interesting CA inhibitory properties. Such hydrosoluble derivatives may show pharmacologic applications. PMID:24746465

  2. Carbonic anhydrase inhibitors. Inhibition of human cytosolic isoforms I and II with (reduced) Schiff's bases incorporating sulfonamide, carboxylate and carboxymethyl moieties.

    PubMed

    Nasr, Gihane; Cristian, Alina; Barboiu, Mihail; Vullo, Daniella; Winum, Jean-Yves; Supuran, Claudiu T

    2014-05-15

    A library of Schiff bases was synthesized by condensation of aromatic amines incorporating sulfonamide, carboxylic acid or carboxymethyl functionalities as Zn(2+)-binding groups, with aromatic aldehydes incorporating tert-butyl, hydroxy and/or methoxy groups. The corresponding amines were thereafter obtained by reduction of the imines. These compounds were assayed for the inhibition of two cytosolic human carbonic anhydrase (hCA, EC 4.2.1.1) isoenzymes, hCA I and II. The Ki values of the Schiff bases were in the range of 7.0-21,400nM against hCA II and of 52-8600nM against hCA I, respectively. The corresponding amines showed Ki values in the range of 8.6nM-5.3μM against hCA II, and of 18.7-251nM against hCA I, respectively. Unlike the imines, the reduced Schiff bases are stable to hydrolysis and several low-nanomolar inhibitors were detected, most of them incorporating sulfonamide groups. Some carboxylates also showed interesting CA inhibitory properties. Such hydrosoluble derivatives may show pharmacologic applications.

  3. Biochemical Issues in Estimation of Cytosolic Free NAD/NADH Ratio

    PubMed Central

    Xie, Jiansheng; Hu, Xun

    2012-01-01

    Cytosolic free NAD/NADH ratio is fundamentally important in maintaining cellular redox homeostasis but current techniques cannot distinguish between protein-bound and free NAD/NADH. Williamson et al reported a method to estimate this ratio by cytosolic lactate/pyruvate (L/P) based on the principle of chemical equilibrium. Numerous studies used L/P ratio to estimate the cytosolic free NAD/NADH ratio by assuming that the conversion in cells was at near-equilibrium but not verifying how near it was. In addition, it seems accepted that cytosolic free NAD/NADH ratio was a dependent variable responding to the change of L/P ratio. In this study, we show (1) that the change of lactate/glucose (percentage of glucose that converts to lactate by cells) and L/P ratio could measure the status of conversion between pyruvate + NADH and lactate + NAD that tends to or gets away from equilibrium; (2) that cytosolic free NAD/NADH could be accurately estimated by L/P only when the conversion is at or very close to equilibrium otherwise a calculation error by one order of magnitude could be introduced; (3) that cytosolic free NAD/NADH is stable and L/P is highly labile, that the highly labile L/P is crucial to maintain the homeostasis of NAD/NADH; (4) that cytosolic free NAD/NADH is dependent on oxygen levels. Our study resolved the key issues regarding accurate estimation of cytosolic free NAD/NADH ratio and the relationship between NAD/NADH and L/P. PMID:22570687

  4. Cytosolic activation of aromatic and heterocyclic amines. Inhibition by dicoumarol and enhancement in viral hepatitis B.

    PubMed Central

    De Flora, S; Bennicelli, C; D'Agostini, F; Izzotti, A; Camoirano, A

    1994-01-01

    The aromatic amines 2-aminofluorene (2AF), 2-acetylaminofluorene, and 2-aminoanthracene, and the heterocyclic amines 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, and 3-amino-1-methyl-SH-pyrido[4,3-b]indole (Trp-P-2) were activated by rat liver cytosolic fractions to form mutagenic metabolites in Salmonella typhimurium strains TA98, TA98NR, and TA98/1,8-DNP6. In the case of the Trp-P-2, the cytosolic activation was even more potent than the microsomal activation, which is classically ascribed to N-hydroxylation and subsequent esterification. The cytosolic activation was a) NADPH-dependent, b) induced by pretreatment of rats with 3-methylcholanthrene and especially Aroclor 1254 but not by phenobarbital, and c) inhibited by dicoumarol. The hypothesis is that, following a preliminary oxidative step in the cytosol (pure cytosolic activation) or in microsomes via prostaglandin H synthase (mixed microsomal-cytosolic activation), an oxidized intermediate of amino compounds may serve as substrate for DT diaphorase activity and bielectronically reduced to the corresponding N-hydroxyamino derivative. Purified DT diaphorase, in the presence of either NADPH or NADH as electron donor, produced mutagenic derivatives from IQ and Trp-P-2. An NADPH-dependent activation of Trp-P-2 also occurred in the liver cytosol of woodchucks (Marmota monax), but was not inhibited by dicoumarol. As previously demonstrated with liver S-12 fractions in both humans and woodchucks, the cytosolic activation of Trp-P-2 was enhanced in animals affected by hepatitis B virus infection. This enhanced metabolism, which persisted even after appearance of primary hepatocellular carcinoma in virus carriers, is likely to be ascribed to mechanisms other than DT diaphorase induction, such as glutathione depletion. PMID:7534225

  5. Role of isothiocyanate conjugate of pterostilbene on the inhibition of MCF-7 cell proliferation and tumor growth in Ehrlich ascitic cell induced tumor bearing mice

    SciTech Connect

    Nikhil, Kumar; Sharan, Shruti; Chakraborty, Ajanta; Bodipati, Naganjaneyulu; Krishna Peddinti, Rama; Roy, Partha

    2014-01-15

    Naturally occurring pterostilbene (PTER) and isothiocyanate (ITC) attract great attention due to their wide range of biological properties, including anti-cancer, anti-leukemic, anti-bacterial and anti-inflammatory activities. A novel class of hybrid compound synthesized by introducing an ITC moiety on PTER backbone was evaluated for its anti-cancer efficacy in hormone-dependent breast cancer cell line (MCF-7) in vitro and Ehrlich ascitic tumor bearing mice model in vivo. The novel hybrid molecule showed significant in vitro anti-cancer activity (IC{sub 50}=25±0.38) when compared to reference compound PTER (IC{sub 50}=65±0.42). The conjugate molecule induced both S and G2/M phase cell cycle arrest as indicated by flow cytometry analysis. In addition, the conjugate induced cell death was characterized by changes in cell morphology, DNA fragmentation, activation of caspase-9, release of cytochrome-c into cytosol and increased Bax: Bcl-2 ratio. The conjugate also suppressed the phosphorylation of Akt and ERK. The conjugate induced cell death was significantly increased in presence of A6730 (a potent Akt1/2 kinase inhibitor) and PD98059 (a specific ERK inhibitor). Moreover, the conjugated PTER inhibited tumor growth in Ehrlich ascitic cell induced tumor bearing mice as observed by reduction in tumor volume compared to untreated animals. Collectively, the pro-apoptotic effect of conjugate is mediated through the activation of caspases, and is correlated with the blockade of the Akt and ERK signaling pathways in MCF-7 cells. - Highlights: • Conjugate was prepared by appending isothiocyanate moiety on pterostilbene backbone. • Conjugate showed anticancer effects at comparatively lower dose than pterostilbene. • Conjugate caused blockage of the Akt and ERK signaling pathways in MCF-7 cells. • Conjugate significantly reduced solid tumor volume as compared to pterostilbene.

  6. INCREASES IN CYTOSOLIC CALCIUM ION LEVELS IN HUMAN NATURAL KILLER CELLS IN RESPONSE TO BUTYLTIN EXPOSURE

    PubMed Central

    Lane, Rhonda; Ghazi, Sabah O.; Whalen, Margaret M.

    2009-01-01

    This study investigated whether exposures to butyltins (BTs), tributylin (TBT) and dibutyltin (DBT) were able to alter cytosolic calcium levels in human natural killer (NK) cells. Additionally, the effects of cytosolic calcium ion increases on the activation state of mitogen activated protein kinases (MAPKs) in NK cells were also investigated. NK cells are an intital immune defense against the development of tumors or viral infections. TBT and DBT are widespread environmental contaminants, due to their various industrial applications. Both TBT and DBT have been shown to decrease the ability of NK cells to lyse tumor cells (lytic function). TBT has also been shown to activate MAPKs in NK cells. The results of this study indicated that TBT increased cytosolic calcium levels by as much as 100% after a 60 min exposure to 500 nM TBT while DBT increased cytosolic calcium levels to a much smaller extent (and required higher concentrations). The results also indicated that increases in cytosolic calcium could activate MAPKs but only for a short period of time (5 min), while previous studies showed that activation of MAPKs by TBT last for at least 6 hours. Thus, it appears that TBT stimulated increases in cytosolic calcium may contribute to, but are not fully responsible for, TBT-induced activation of MAPKs. PMID:19365649

  7. Overexpression of mitochondrial ferritin causes cytosolic iron depletion and changes cellular iron homeostasis.

    PubMed

    Nie, Guangjun; Sheftel, Alex D; Kim, Sangwon F; Ponka, Prem

    2005-03-01

    Cytosolic ferritin sequesters and stores iron and, consequently, protects cells against iron-mediated free radical damage. However, the function of the newly discovered mitochondrial ferritin (MtFt) is unknown. To examine the role of MtFt in cellular iron metabolism, we established a cell line that stably overexpresses mouse MtFt under the control of a tetracycline-responsive promoter. The overexpression of MtFt caused a dose-dependent iron deficiency in the cytosol that was revealed by increased RNA-binding activity of iron regulatory proteins (IRPs) along with an increase in transferrin receptor levels and decrease in cytosolic ferritin. Consequently, the induction of MtFt resulted in a dramatic increase in cellular iron uptake from transferrin, most of which was incorporated into MtFt. The induction of MtFt caused a shift of iron from cytosolic ferritin to MtFt. In addition, iron inserted into MtFt was less available for chelation than that in cytosolic ferritin and the expression of MtFt was associated with decreased mitochondrial and cytosolic aconitase activities, the latter being consistent with the increase in IRP-binding activity. In conclusion, our results indicate that overexpression of MtFt causes a dramatic change in intracellular iron homeostasis and that shunting iron to MtFt likely limits its availability for active iron proteins.

  8. Cotransin induces accumulation of a cytotoxic clusterin variant that cotranslationally rerouted to the cytosol

    SciTech Connect

    Choi, Ilho; Kim, Jiyeon; Park, Joong-Yeol; Kang, Sang-Wook

    2013-05-01

    Although clusterin (CLU) was originally identified as a secreted glycoprotein that plays cytoprotective role, several intracellular CLU variants have been recently identified in the diverse pathological conditions. The mechanistic basis of these variants is now believed to be alternative splicing and retrotranslocation. Here, we uncovered, an unglycosylated and signal sequence-unprocessed, CLU variant in the cytosol. This variant proved to be a product that cotranslationally rerouted to the cytosol during translocation. Cytosolic CLU was prone to aggregation at peri-nuclear region of cells and induced cell death. Signal sequence is shown to be an important determinant for cytosolic CLU generation and aggregation. These results provide not only a new mechanistic insight into the cytosolic CLU generation but also an idea for therapeutic mislocalization of CLU as a strategy for cancer treatment. - Highlights: ► Intracellular CLU variants have been recently identified in the diverse pathological conditions. ► Translocation of clusterin is less efficient than that of Prl. ► We identified a new cytotoxic clusterin variant whose signal sequence was unprocessed. ► This variant proved to be a product that cotranslationally rerouted to cytosol.

  9. Requirements of the cytosolic iron–sulfur cluster assembly pathway in Arabidopsis

    PubMed Central

    Bernard, Delphine G.; Netz, Daili J. A.; Lagny, Thibaut J.; Pierik, Antonio J.; Balk, Janneke

    2013-01-01

    The assembly of iron–sulfur (Fe–S) clusters requires dedicated protein factors inside the living cell. Striking similarities between prokaryotic and eukaryotic assembly proteins suggest that plant cells inherited two different pathways through endosymbiosis: the ISC pathway in mitochondria and the SUF pathway in plastids. Fe–S proteins are also found in the cytosol and nucleus, but little is known about how they are assembled in plant cells. Here, we show that neither plastid assembly proteins nor the cytosolic cysteine desulfurase ABA3 are required for the activity of cytosolic aconitase, which depends on a [4Fe–4S] cluster. In contrast, cytosolic aconitase activity depended on the mitochondrial cysteine desulfurase NFS1 and the mitochondrial transporter ATM3. In addition, we were able to complement a yeast mutant in the cytosolic Fe–S cluster assembly pathway, dre2, with the Arabidopsis homologue AtDRE2, but only when expressed together with the diflavin reductase AtTAH18. Spectroscopic characterization showed that purified AtDRE2 could bind up to two Fe–S clusters. Purified AtTAH18 bound one flavin per molecule and was able to accept electrons from NAD(P)H. These results suggest that the proteins involved in cytosolic Fe–S cluster assembly are highly conserved, and that dependence on the mitochondria arose before the second endosymbiosis event leading to plastids. PMID:23754812

  10. Vascular Bioactivation of Nitroglycerin by Aldehyde Dehydrogenase-2

    PubMed Central

    Lang, Barbara S.; Gorren, Antonius C. F.; Oberdorfer, Gustav; Wenzl, M. Verena; Furdui, Cristina M.; Poole, Leslie B.; Mayer, Bernd; Gruber, Karl

    2012-01-01

    Aldehyde dehydrogenase-2 (ALDH2) catalyzes the bioactivation of nitroglycerin (glyceryl trinitrate, GTN) in blood vessels, resulting in vasodilation by nitric oxide (NO) or a related species. Because the mechanism of this reaction is still unclear we determined the three-dimensional structures of wild-type (WT) ALDH2 and of a triple mutant of the protein that exhibits low denitration activity (E268Q/C301S/C303S) in complex with GTN. The structure of the triple mutant showed that GTN binds to the active site via polar contacts to the oxyanion hole and to residues 268 and 301 as well as by van der Waals interactions to hydrophobic residues of the catalytic pocket. The structure of the GTN-soaked wild-type protein revealed a thionitrate adduct to Cys-302 as the first reaction intermediate, which was also found by mass spectrometry (MS) experiments. In addition, the MS data identified sulfinic acid as the irreversibly inactivated enzyme species. Assuming that the structures of the triple mutant and wild-type ALDH2 reflect binding of GTN to the catalytic site and the first reaction step, respectively, superposition of the two structures indicates that denitration of GTN is initiated by nucleophilic attack of Cys-302 at one of the terminal nitrate groups, resulting in formation of the observed thionitrate intermediate and release of 1,2-glyceryl dinitrate. Our results shed light on the molecular mechanism of the GTN denitration reaction and provide useful information on the structural requirements for high affinity binding of organic nitrates to the catalytic site of ALDH2. PMID:22988236

  11. Residues that influence coenzyme preference in the aldehyde dehydrogenases.

    PubMed

    González-Segura, Lilian; Riveros-Rosas, Héctor; Julián-Sánchez, Adriana; Muñoz-Clares, Rosario A

    2015-06-01

    To find out the residues that influence the coenzyme preference of aldehyde dehydrogenases (ALDHs), we reviewed, analyzed and correlated data from their known crystal structures and amino-acid sequences with their published kinetic parameters for NAD(P)(+). We found that the conformation of the Rossmann-fold loops participating in binding the adenosine ribose is very conserved among ALDHs, so that coenzyme specificity is mainly determined by the nature of the residue at position 195 (human ALDH2 numbering). Enzymes with glutamate or proline at 195 prefer NAD(+) because the side-chains of these residues electrostatically and/or sterically repel the 2'-phosphate group of NADP(+). But contrary to the conformational rigidity of proline, the conformational flexibility of glutamate may allow NADP(+)-binding in some enzymes by moving the carboxyl group away from the 2'-phosphate group, which is possible if a small neutral residue is located at position 224, and favored if the residue at position 53 interacts with Glu195 in a NADP(+)-compatible conformation. Of the residues found at position 195, only glutamate interacts with the NAD(+)-adenosine ribose; glutamine and histidine cannot since their side-chain points are opposite to the ribose, probably because the absence of the electrostatic attraction by the conserved nearby Lys192, or its electrostatic repulsion, respectively. The shorter side-chains of other residues-aspartate, serine, threonine, alanine, valine, leucine, or isoleucine-are distant from the ribose but leave room for binding the 2'-phosphate group. Generally, enzymes having a residue different from Glu bind NAD(+) with less affinity, but they can also bind NADP(+) even sometimes with higher affinity than NAD(+), as do enzymes containing Thr/Ser/Gln195. Coenzyme preference is a variable feature within many ALDH families, consistent with being mainly dependent on a single residue that apparently has no other structural or functional roles, and therefore can

  12. Aldehyde measurements in indoor environments in Strasbourg (France)

    NASA Astrophysics Data System (ADS)

    Marchand, C.; Bulliot, B.; Le Calvé, S.; Mirabel, Ph.

    Formaldehyde and acetaldehyde concentrations have been measured in indoor environments of various public spaces (railway station, airport, shopping center, libraries, underground parking garage, etc.) of Strasbourg area (east of France). In addition, formaldehyde, acetaldehyde propionaldehyde and hexanal concentrations have been measured in 22 private homes in the same area. In most of the sampling sites, indoor and outdoor formaldehyde and acetaldehyde concentrations were measured simultaneously. Gaseous aldehydes levels were quantified by a conventional DNHP-derivatization method followed by liquid chromatography coupled to UV detection. Outdoor formaldehyde and acetaldehyde concentrations were both in the range 1-10 μg m -3, the highest values being measured at the airport and railway station. Indoor concentrations were strongly dependant upon the sampling sites. In homes, the average concentrations were 37 μg m -3 (living rooms) and 46 μg m -3 (bedrooms) for formaldehyde, 15 μg m -3 (living rooms) and 18 μg m -3 (bedrooms) for acetaldehyde, 1.2 μg m -3 (living rooms) and 1.6 μg m -3 (bedrooms) for propionaldehyde, 9 μg m -3 (living rooms) and 10 μg m -3 (bedrooms) for hexanal. However, concentrations as high as 123, 80 and 47 μg m -3 have been found for formaldehyde, acetaldehyde and hexanal respectively. In public spaces, the highest formaldehyde concentration (62 μg m -3) was found in a library and the highest concentration of acetaldehyde (26 μg m -3) in the hall of a shopping center. Additional measurements of formaldehyde and acetaldehyde were made inside a car both at rest or in a fluid or heavy traffic as well as in a room where cigarettes were smoked. Our data have been discussed and compared with those of previous studies.

  13. 4-(2-aminooxyethoxy)-2-(ethylureido)quinoline-oligonucleotide conjugates: synthesis, binding interactions, and derivatization with peptides.

    PubMed

    Hamma, Tomoko; Miller, Paul S

    2003-01-01

    Oligo-2'-O-methylribonucleotides conjugated with 4-(2-aminooxyethoxy)-2-(ethylureido)quinoline (AOQ) and 4-ethoxy-2-(ethylureido)quinoline (EOQ) were prepared by reaction of the AOQ or EOQ phosphoramidite with the protected oligonucleotide on a controlled pore glass support. Deprotection with ethylenediamine enabled successful isolation and purification of the highly reactive AOQ-conjugated oligomer. Polyacrylamide gel electrophoresis mobility shift experiments showed that the dissociation constants of complexes formed between an AOQ- or EOQ-conjugated 8-mer and complementary RNA or 2'-O-methyl-RNA targets (9- and 10-mers) were in the low nM concentration range at 37 degrees C, whereas no binding was observed for the corresponding nonconjugated oligomer, even at a concentration of 500 nM. Fluorescence studies suggested that this enhanced affinity is most likely due to the ability of the quinoline ring of the AOQ or EOQ group to stack on the last base pair formed between the oligomer and target, thus stabilizing the duplex. The binding affinity of a 2'-O-methyl RNA 15-mer, which contained an alternating methylphosphonate/phosphodiester backbone, for a 59-nucleotide stem-loop HIV TAR RNA target, increased 2.3 times as a consequence of conjugation with EOQ. The aminooxy group of AOQ-conjugated oligomers is a highly reactive nucleophile, which reacts readily with aldehydes and ketones to form stable oxime derivatives. This feature was used to couple an AOQ-oligomer with leupeptin, a tripeptide that contains a C-terminus aldehyde group. A simple method was developed to introduce a ketone functionality into peptides that contain a cysteine residue by reacting the peptide with bromoacetone. The resulting keto-peptide was then coupled to the AOQ-oligomer. This procedure was used to prepare oligonucleotide conjugates of a tetrapeptide, RGDC, and a derivative of HIV tat peptide having a C-terminus cysteine. The combination of the unique reactivity of the aminooxy group and

  14. Gender and conjugal differences in happiness.

    PubMed

    Lu, L

    2000-02-01

    The author examined conjugal congruence on 4 role experiences--spousal, parental, filial, worker--and on subjective well-being (SWB). According to purposive sampling strategy, 222 community adults (111 married couples) in Taiwan completed a research questionnaire. Conjugal congruence on role experiences was linked to conjugal congruence on SWB as well as personal well-being. Analyses showed that conjugal congruence on role experiences (except the worker role) and SWB was generally high. However, some conjugal discrepancies persisted: The husbands were more committed to the worker role, whereas the wives were more committed to the parental role. Furthermore, conjugal discrepancies in role experiences were related to conjugal discrepancies in SWB as well as to husbands' happiness.

  15. Effect of commonly used organic solvents on aldehyde oxidase-mediated vanillin, phthalazine and methotrexate oxidation in human, rat and mouse liver subcellular fractions.

    PubMed

    Behera, Dayanidhi; Pattem, Rambabu; Gudi, Girish

    2014-08-01

    1. Aldehyde oxidase (AOX) is a cytosolic molybdoflavoprotein enzyme widely distributed across many tissues. In this study, we report the effect of commonly used organic solvents such as dimethyl sulfoxide (DMSO), acetonitrile (ACN), methanol and ethanol on AOX activity in human, rat and mouse liver S9 fractions using vanillin, phthalazine and methotrexate as probe substrates. 2. Methanol was found to be the most potent solvent in inhibiting vanillic acid and 1-phthalazinone formation in comparison to DMSO, ACN and ethanol across the species tested, except 7-hydroxy methotrexate. 3. Treatment with these solvents at approximate IC50 (% v/v) concentrations showed significant reduction in Clint and Vmax of the probe substrates and also resulted in different effects on Km across the species. 4. Marked differences in the activity and affinity towards AOX were observed with different probe substrates with methotrexate showing least activity and affinity as compared to vanillin and phthalazine. 5. Overall, AOX activity seemed to be more resilient to the presence of organic solvents at higher concentrations in human and rodent species. These results suggest that low concentrations of organic solvents are acceptable for in vitro incubations involving AOX-mediated metabolism.

  16. 9-O-acetylated sialic acids differentiating normal haematopoietic precursors from leukemic stem cells with high aldehyde dehydrogenase activity in children with acute lymphoblastic leukaemia.

    PubMed

    Chowdhury, Suchandra; Chandra, Sarmila; Mandal, Chitra

    2014-10-01

    Childhood acute lymphoblastic leukaemia (ALL) originates from mutations in haematopoietic progenitor cells (HPCs). For high-risk patients, treated with intensified post-remission chemotherapy, haematopoietic stem cell (HSC) transplantation is considered. Autologous HSC transplantation needs improvisation till date. Previous studies established enhanced disease-associated expression of 9-O-acetylated sialoglycoproteins (Neu5,9Ac2-GPs) on lymphoblasts of these patients at diagnosis, followed by its decrease with clinical remission and reappearance with relapse. Based on this differential expression of Neu5,9Ac2-GPs, identification of a normal HPC population was targeted from patients at diagnosis. This study identifies two distinct haematopoietic progenitor populations from bone marrow of diagnostic ALL patients, exploring the differential expression of Neu5,9Ac2-GPs with stem cell (CD34, CD90, CD117, CD133), haematopoietic (CD45), lineage-commitment (CD38) antigens and cytosolic aldehyde dehydrogenase (ALDH). Normal haematopoietic progenitor cells (ALDH(+)SSC(lo)CD45(hi)Neu5,9Ac2 -GPs(lo)CD34(+)CD38(-)CD90(+)CD117(+)CD133(+)) differentiated into morphologically different, lineage-specific colonies, being crucial for autologous HSC transplantation while leukemic stem cells (ALDH(+)SSC(lo)CD45(lo)Neu5,9Ac2 -GPs(hi)CD34(+)CD38(+)CD90(-)CD117(-)CD133(-)) lacking this ability can be potential targets for minimal residual disease detection and drug-targeted immunotherapy.

  17. Intracellular delivery and trafficking dynamics of a lymphoma-targeting antibody-polymer conjugate.

    PubMed

    Berguig, Geoffrey Y; Convertine, Anthony J; Shi, Julie; Palanca-Wessels, Maria Corinna; Duvall, Craig L; Pun, Suzie H; Press, Oliver W; Stayton, Patrick S

    2012-12-01

    Ratiometric fluorescence and cellular fractionation studies were employed to characterize the intracellular trafficking dynamics of antibody-poly(propylacrylic acid) (PPAA) conjugates in CD22+ RAMOS-AW cells. The HD39 monoclonal antibody (mAb) directs CD22-dependent, receptor-mediated uptake in human B-cell lymphoma cells, where it is rapidly trafficked to the lysosomal compartment. To characterize the intracellular-release dynamics of the polymer-mAb conjugates, HD39-streptavidin (HD39/SA) was dual-labeled with pH-insensitive Alexa Fluor 488 and pH-sensitive pHrodo fluorophores. The subcellular pH distribution of the HD39/SA-polymer conjugates was quantified as a function of time by live-cell fluorescence microscopy, and the average intracellular pH value experienced by the conjugates was also characterized as a function of time by flow cytometry. PPAA was shown to alter the intracellular trafficking kinetics strongly relative to HD39/SA alone or HD39/SA conjugates with a control polymer, poly(methacryclic acid) (PMAA). Subcellular trafficking studies revealed that after 6 h, only 11% of the HD39/SA-PPAA conjugates had been trafficked to acidic lysosomal compartments with values at or below pH 5.6. In contrast, the average intracellular pH of HD39/SA alone dropped from 6.7 ± 0.2 at 1 h to 5.6 ± 0.5 after 3 h and 4.7 ± 0.6 after 6 h. Conjugation of the control polymer PMAA to HD39/SA showed an average pH drop similar to that of HD39/SA. Subcellular fractionation studies with tritium-labeled HD39/SA demonstrated that after 6 h, 89% of HD39/SA was associated with endosomes (Rab5+) and lysosomes (Lamp2+), while 45% of HD39/SA-PPAA was translocated to the cytosol (lactate dehydrogenase+). These results demonstrate the endosomal-releasing properties of PPAA with antibody-polymer conjugates and detail their intracellular trafficking dynamics and subcellular compartmental distributions over time.

  18. Identification and characterization of an antennae-specific aldehyde oxidase from the navel orangeworm.

    PubMed

    Choo, Young-Moo; Pelletier, Julien; Atungulu, Elizabeth; Leal, Walter S

    2013-01-01

    Antennae-specific odorant-degrading enzymes (ODEs) are postulated to inactivate odorant molecules after they convey their signal. Different classes of insect ODEs are specific to esters, alcohols, and aldehydes--the major functional groups of female-produced, hydrophobic sex pheromones from moth species. Esterases that rapidly inactive acetate and other esters have been well-studied, but less is known about aldehyde oxidases (AOXs). Here we report cloning of an aldehyde oxidase, AtraAOX2, from the antennae of the navel orangeworm (NOW), Amyelois transitella, and the first activity characterization of a recombinant insect AOX. AtraAOX2 gene spans 3,813 bp and encodes a protein with 1,270 amino acid residues. AtraAOX2 cDNA was expressed in baculovirus-infected insect Sf21 cells as a ≈280 kDa homodimer with 140 kDa subunits. Recombinant AtraAOX2 degraded Z11Z13-16Ald and plant volatile aldehydes as substrates. However, as expected for aldehyde oxidases, recombinant AtraAOX2 did not show specificity for Z11Z13-16Ald, the main constituent of the sex pheromone, but showed high activity for plant volatile aldehydes. Our data suggest AtraAOX2 might be involved in degradation of a diversity of aldehydes including sex pheromones, plant-derived semiochemicals, and chemical cues for oviposition sites. Additionally, AtraAOX2 could protect the insect's olfactory system from xenobiotics, including pesticides that might reach the sensillar lymph surrounding the olfactory receptor neurons. PMID:23826341

  19. Determination of lipid ester ozonides and core aldehydes by high-performance liquid chromatography with on-line mass spectrometry.

    PubMed

    Ravandi, A; Kuksis, A; Myher, J J; Marai, L

    1995-11-01

    Unsaturated triacylglycerols (TG) and choline (PC) and ethanolamine (PE) phosphatides of known structure were subjected to ozonization and reduction with triphenylphosphine to yield the corresponding lipid ester core aldehydes. Mono- and di-C9 aldehyde palmitoylglycerols were prepared from oleoyldipalmitoyl and oleoyllinoleoylpalmitoyl glycerols, respectively, while egg yolk PC and PE provided the mono-C5 and mono-C9 aldehydes of palmitoyl-and stearoyl glycerophospholipids. The aldehydes were isolated in the free form and as the dinitrophenylhydrazone (DNPH) derivatives by thin-layer chromatography (TLC). The intermediate ozonides, free aldehydes and hydrazones were identified by reversed phase high performance liquid chromatography (HPLC) with on-line negative ion thermospray and normal phase HPLC with on-line positive ion electrospray mass spectrometry (LC-MS). The synthetic aldehydes were used as carriers during isolation from natural sources and as reference compounds in quantitative analyses.

  20. The ISG15 conjugation system.

    PubMed

    Durfee, Larissa A; Huibregtse, Jon M

    2012-01-01

    ISG15 is a ubiquitin-like modifier that is expressed in response to type 1 interferon signaling (IFN-α/β) and plays a role in antiviral responses. The core E1, E2, and E3 enzymes for ISG15 are Ube1L, UbcH8, and Herc5, respectively, and these are all also induced at the transcriptional level by IFN-α/β. We recently showed that Herc5 associates with polysomes and modifies target proteins in a cotranslational manner. Here, we describe the expression of the core conjugating enzymes in human cells, the detection of ISG15 conjugates, and the methods for fractionation of Herc5 with polysomes. PMID:22350882

  1. Enhanced photophysics of conjugated polymers

    DOEpatents

    Chen, Liaohai; Xu, Su; McBranch, Duncan; Whitten, David

    2003-05-27

    The addition of oppositely charged surfactant to fluorescent ionic conjugated polymer forms a polymer-surfactant complex that exhibits at least one improved photophysical property. The conjugated polymer is a fluorescent ionic polymer that typically has at least one ionic side chain or moiety that interacts with the specific surfactant selected. The photophysical property improvements may include increased fluorescence quantum efficiency, wavelength-independent emission and absorption spectra, and more stable fluorescence decay kinetics. The complexation typically occurs in a solution of a polar solvent in which the polymer and surfactant are soluble, but it may also occur in a mixture of solvents. The solution is commonly prepared with a surfactant molecule:monomer repeat unit of polymer ratio ranging from about 1:100 to about 1:1. A polymer-surfactant complex precipitate is formed as the ratio approaches 1:1. This precipitate is recoverable and usable in many forms.

  2. Variable metric conjugate gradient methods

    SciTech Connect

    Barth, T.; Manteuffel, T.

    1994-07-01

    1.1 Motivation. In this paper we present a framework that includes many well known iterative methods for the solution of nonsymmetric linear systems of equations, Ax = b. Section 2 begins with a brief review of the conjugate gradient method. Next, we describe a broader class of methods, known as projection methods, to which the conjugate gradient (CG) method and most conjugate gradient-like methods belong. The concept of a method having either a fixed or a variable metric is introduced. Methods that have a metric are referred to as either fixed or variable metric methods. Some relationships between projection methods and fixed (variable) metric methods are discussed. The main emphasis of the remainder of this paper is on variable metric methods. In Section 3 we show how the biconjugate gradient (BCG), and the quasi-minimal residual (QMR) methods fit into this framework as variable metric methods. By modifying the underlying Lanczos biorthogonalization process used in the implementation of BCG and QMR, we obtain other variable metric methods. These, we refer to as generalizations of BCG and QMR.

  3. Monitoring cytosolic and ER Zn(2+) in stimulated breast cancer cells using genetically encoded FRET sensors.

    PubMed

    Hessels, Anne M; Taylor, Kathryn M; Merkx, Maarten

    2016-02-01

    The Zn(2+)-specific ion channel ZIP7 has been implicated to play an important role in releasing Zn(2+) from the ER. External stimulation of breast cancer cells has been proposed to induce phosphorylation of ZIP7 by CK2α, resulting in ZIP7-mediated Zn(2+) release from the ER into the cytosol. Here, we examined whether changes in cytosolic and ER Zn(2+) concentrations can be detected upon such external stimuli. Two previously developed FRET sensors for Zn(2+), eZinCh-2 (Kd = 1 nM at pH 7.1) and eCALWY-4 (Kd = 0.63 nM at pH 7.1), were expressed in both the cytosol and the ER of wild-type MCF-7 and TamR cells. Treatment of MCF-7 and TamR cells with external Zn(2+) and pyrithione, one of the previously used triggers, resulted in an immediate increase in free Zn(2+) in both cytosol and ER, suggesting that Zn(2+) was directly transferred across the cellular membranes by pyrithione. Cells treated with a second trigger, EGF/ionomycin, showed no changes in intracellular Zn(2+) levels, neither in multicolor imaging experiments that allowed simultaneous imaging of cytosolic and ER Zn(2+), nor in experiments in which cytosolic and ER Zn(2+) were monitored separately. In contrast to previous work using small-molecule fluorescent dyes, these results indicate that EGF-ionomycin treatment does not result in significant changes in cytosolic Zn(2+) levels as a result from Zn(2+) release from the ER. These results underline the importance of using genetically encoded fluorescent sensors to complement and verify intracellular imaging experiments with synthetic fluorescent Zn(2+) dyes. PMID:26739447

  4. Isobutyraldehyde production from Escherichia coli by removing aldehyde reductase activity

    PubMed Central

    2012-01-01

    Background Increasing global demand and reliance on petroleum-derived chemicals will necessitate alternative sources for chemical feedstocks. Currently, 99% of chemical feedstocks are derived from petroleum and natural gas. Renewable methods for producing important chemical feedstocks largely remain unaddressed. Synthetic biology enables the renewable production of various chemicals from microorganisms by constructing unique metabolic pathways. Here, we engineer Escherichia coli for the production of isobutyraldehyde, which can be readily converted to various hydrocarbons currently derived from petroleum such as isobutyric acid, acetal, oxime and imine using existing chemical catalysis. Isobutyraldehyde can be readily stripped from cultures during production, which reduces toxic effects of isobutyraldehyde. Results We adopted the isobutanol pathway previously constructed in E. coli, neglecting the last step in the pathway where isobutyraldehyde is converted to isobutanol. However, this strain still overwhelmingly produced isobutanol (1.5 g/L/OD600 (isobutanol) vs 0.14 g/L/OD600 (isobutyraldehyde)). Next, we deleted yqhD which encodes a broad-substrate range aldehyde reductase known to be active toward isobutyraldehyde. This strain produced isobutanol and isobutyraldehyde at a near 1:1 ratio, indicating further native isobutyraldehyde reductase (IBR) activity in E. coli. To further eliminate isobutanol formation, we set out to identify and remove the remaining IBRs from the E. coli genome. We identified 7 annotated genes coding for IBRs that could be active toward isobutyraldehyde: adhP, eutG, yiaY, yjgB, betA, fucO, eutE. Individual deletions of the genes yielded only marginal improvements. Therefore, we sequentially deleted all seven of the genes and assessed production. The combined deletions greatly increased isobutyraldehyde production (1.5 g/L/OD600) and decreased isobutanol production (0.4 g/L/OD600). By assessing production by overexpression of each

  5. Difunctional and heterocyclic products from the ozonolysis of conjugated C sub 5 -C sub 8 cyclodienes

    SciTech Connect

    Griesbaum, K.; In Chan Jung; Mertens, H. )

    1990-11-23

    Ozonolyses of the conjugated C{sub 5}-C{sub 8} cyclodienes 1a-d in methanol, followed by reduction with DMS, have been examined. Monoozonolyses gave the corresponding unsaturated dialdehydes 2e as the primary products. In subsequent reactions, the dialdehydes 2e derived from the monoozonolyses of 1a, 1b, and 1c gave in high yields the heterocyclic compounds 7, 8k, and 9k, respectively. Diozonolyses of 1a-d gave the corresponding dialdehydes 3e as the primary products. In subsequent reactions, the dialdehydes 3e derived from 1b and 1c gave the heterocyclic compounds 8l, and 9l, respectively. In addition, aldehydes 2e and 3e underwent partial acetalization reactions with methanol.

  6. Photophysical studies of fused phenanthrimidazole derivatives as versatile π-conjugated systems for potential NLO applications.

    PubMed

    Jayabharathi, Jayaraman; Thanikachalam, Venugopal; Perumal, Marimuthu Venkatesh

    2012-06-15

    Two new heterocyclic imidazole derivatives consists of π-conjugated system attached to a phenanthrimidazole moiety have been synthesized in moderate yield by the condensation of 1,10-phenanthroline-5,6-dione with substituted aromatic aldehydes and 4-methoxyaniline in the presence of ammonium acetate in ethanol medium. The photophysical properties of these imidazole derivatives were studied in several solvents. These derivatives were evaluated concerning their solvatochromic properties and molecular optical nonlinearities. Their electric dipole moment (μ) and hyperpolarizability (β) have been calculated theoretically and the results indicate that the extension of the π-framework of the ligands has an effect on the NLO properties of these imidazole derivatives. The non-zero tensor components of these imidazole derivatives reveal that they possess potent non-linear optical (NLO) behavior. The energies of the HOMO and LUMO levels and the molecular electrostatic potential (MEP) energy surface studies have exploited the existence of intramolecular charge transfer (ICT) within the molecule.

  7. Use of Ribosome-Inactivating Proteins from Sambucus for the Construction of Immunotoxins and Conjugates for Cancer Therapy

    PubMed Central

    Ferreras, José M.; Citores, Lucía; Iglesias, Rosario; Jiménez, Pilar; Girbés, Tomás

    2011-01-01

    The type 2 ribosome-inactivating proteins (RIPs) isolated from some species belonging to the Sambucus genus, have the characteristic that although being even more active than ricin inhibiting protein synthesis in cell-free extracts, they lack the high toxicity of ricin and related type 2 RIPs to intact cells and animals. This is due to the fact that after internalization, they follow a different intracellular pathway that does not allow them to reach the cytosolic ribosomes. The lack of toxicity of type 2 RIPs from Sambucus make them good candidates as toxic moieties in the construction of immunotoxins and conjugates directed against specific targets. Up to now they have been conjugated with either transferrin or anti-CD105 to target either transferrin receptor- or endoglin-overexpressing cells, respectively. PMID:22069717

  8. Quantification of aldehydes emissions from alternative and renewable aviation fuels using a gas turbine engine

    NASA Astrophysics Data System (ADS)

    Li, Hu; Altaher, Mohamed A.; Wilson, Chris W.; Blakey, Simon; Chung, Winson; Rye, Lucas

    2014-02-01

    In this research three renewable aviation fuel blends including two HEFA (Hydrotreated Ester and Fatty Acid) blends and one FAE (Fatty Acids Ethyl Ester) blend with conventional Jet A-1 along with a GTL (Gas To Liquid) fuel have been tested for their aldehydes emissions on a small gas turbine engine. Three strong ozone formation precursors: formaldehyde, acetaldehyde and acrolein were measured in the exhaust at different operational modes and compared to neat Jet A-1. The aim is to assess the impact of renewable and alternative aviation fuels on aldehydes emissions from aircraft gas turbine engines so as to provide informed knowledge for the future deployment of new fuels in aviation. The results show that formaldehyde was a major aldehyde species emitted with a fraction of around 60% of total measured aldehydes emissions for all fuels. Acrolein was the second major emitted aldehyde species with a fraction of ˜30%. Acetaldehyde emissions were very low for all the fuels and below the detention limit of the instrument. The formaldehyde emissions at cold idle were up to two to threefold higher than that at full power. The fractions of formaldehyde were 6-10% and 20% of total hydrocarbon emissions in ppm at idle and full power respectively and doubled on a g kg-1-fuel basis.

  9. Charged tag founded in N-(1-chloroalkyl)pyridinium quaternization for quantification of fatty aldehydes.

    PubMed

    Cao, Yanjing; Guan, Qing; Sun, Tuanqi; Qi, Wanshu; Guo, Yinlong

    2016-09-21

    N-(1-chloroalkyl)pyridinium quaternization was developed for the derivatization of fatty aldehydes. Differing from common pre-charged reagents, non-charged pyridine and thionyl chloride were designed to add permanently charged tag on aldehydes. Pyridine was far less competitive than charged derivatives in ionization. Thionyl chloride in excess was quenched by deionized water, converting into less residual sulfur dioxide bubbles. Thus solutions could be tested directly by mass spectrometry without further post-treatments. Pyridine-d5 labeled fatty aldehydes were prepared as internal standards. Mixed derivatives were then analyzed by high performance liquid chromatography coupled to positive electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). Analytical parameters including reaction yield, stability, precision, linearity, and detection limits (LODs < 0.3 pg mL(-1)) were carefully validated. This method facilitated the analysis low content (ng mL(-1)) levels of free aliphatic aldehydes (C6C18) in human thyroid carcinoma and para-carcinoma tissue with a simple pretreatment procedure. Content of long chain nonvolatile aldehydes (C10C18) remarkably increased in thyroid carcinoma tissues (p < 0.05). PMID:27590548

  10. Aldehydes in Artic Snow at Barrow (AK) during the Barrow 2009 Field Campaign

    NASA Astrophysics Data System (ADS)

    Barret, Manuel; Houdier, Stephan; Gallet, Jean-Charles; Domine, Florent; Beine, Harry; Jacobi, Hans-Werner; Weibring, Petter; Walega, James; Fried, Alan; Richter, Dirk

    2010-05-01

    Aldehydes (RCHO) are key reactive intermediates in hydrocarbon oxidation and in OH cycling. They are also emitted and taken up by the snowpack and a combination of both physical and photochemical processes are likely involved. Since the photolysis of aldehydes is a source of HOx radicals, these exchanges can modify the oxidative capacity of the overlying air. Formaldehyde (HCHO), acetaldehyde (MeCHO), glyoxal (CHOCHO) and methylglyoxal (MeCOCHO) concentrations were measured in over 250 snow samples collected during the Barrow 2009 campaign between late February and mid April 2009. Both continental and marine snowpacks were studied as well as frost flowers on sea ice. We found that HCHO was the most abundant aldehyde (1 to 9 µg/L), but significant concentrations of dicarbonyls glyoxal and methylglyoxal were also measured for the first time in Arctic snow. Similar concentrations were measured for the continental and marine snowpacks but some frost flowers exhibited HCHO concentrations as high as 150 µg/L. Daily cycles in the surface snow were observed for HCHO and CH3CHO but also for the dicarbonyls and we concluded to a photochemical production of these species from organic precursors. Additional data such as gas phase concentrations for the measured aldehydes and snow physical properties (specific surface area, density …) will be used to discuss on the location of aldehydes in the snow. This is essential to identify and quantify the physical processes that occur during the exchange of trace gases between the snow and the atmosphere.

  11. Toxicity of polyunsaturated aldehydes of diatoms to Indo-Pacific bioindicator organism Echinometra mathaei.

    PubMed

    Sartori, Davide; Gaion, Andrea

    2016-01-01

    Although it is well known suitability of early developmental stages of sea urchin as recommended model for pollutant toxicity testing, little is known about the sensitivity of Indo-Pacific species Echinometra mathaei to polyunsaturated aldehydes. In this study, the effect of three short chain aldehydes, 2,4-decadienal (DD), 2,4-octadienal (OD) and 2,4-heptadienal (HD), normally found in many diatoms, such as Skeletonema costatum, Skeletonema marinoi and Thalassiosira rotula, was evaluated on larval development of E. mathaei embryos. Aldehydes affected larval development in a dose-dependent manner, in particular HD>OD>DD; the results of this study highlighted the higher sensitivity of this species toward aldehydes compared with data registered for other sea urchin species. In comparison with studies reported in the literature, contrasting results were observed during our tests; therefore, an increasing toxic effect was registered with decreasing the chain length of aldehydes. This work could provide new insights in the development of new toxicological assays toward most sensitive species. PMID:25945412

  12. Charged tag founded in N-(1-chloroalkyl)pyridinium quaternization for quantification of fatty aldehydes.

    PubMed

    Cao, Yanjing; Guan, Qing; Sun, Tuanqi; Qi, Wanshu; Guo, Yinlong

    2016-09-21

    N-(1-chloroalkyl)pyridinium quaternization was developed for the derivatization of fatty aldehydes. Differing from common pre-charged reagents, non-charged pyridine and thionyl chloride were designed to add permanently charged tag on aldehydes. Pyridine was far less competitive than charged derivatives in ionization. Thionyl chloride in excess was quenched by deionized water, converting into less residual sulfur dioxide bubbles. Thus solutions could be tested directly by mass spectrometry without further post-treatments. Pyridine-d5 labeled fatty aldehydes were prepared as internal standards. Mixed derivatives were then analyzed by high performance liquid chromatography coupled to positive electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). Analytical parameters including reaction yield, stability, precision, linearity, and detection limits (LODs < 0.3 pg mL(-1)) were carefully validated. This method facilitated the analysis low content (ng mL(-1)) levels of free aliphatic aldehydes (C6C18) in human thyroid carcinoma and para-carcinoma tissue with a simple pretreatment procedure. Content of long chain nonvolatile aldehydes (C10C18) remarkably increased in thyroid carcinoma tissues (p < 0.05).

  13. Evaluation of the toxicity of stress-related aldehydes to photosynthesis in chloroplasts.

    PubMed

    Mano, Jun'ichi; Miyatake, Fumitaka; Hiraoka, Eiji; Tamoi, Masahiro

    2009-09-01

    Aldehydes produced under various environmental stresses can cause cellular injury in plants, but their toxicology in photosynthesis has been scarcely investigated. We here evaluated their effects on photosynthetic reactions in chloroplasts isolated from Spinacia oleracea L. leaves. Aldehydes that are known to stem from lipid peroxides inactivated the CO(2) photoreduction to various extents, while their corresponding alcohols and carboxylic acids did not affect photosynthesis. alpha,beta-Unsaturated aldehydes (2-alkenals) showed greater inactivation than the saturated aliphatic aldehydes. The oxygenated short aldehydes malondialdehyde, methylglyoxal, glycolaldehyde and glyceraldehyde showed only weak toxicity to photosynthesis. Among tested 2-alkenals, 2-propenal (acrolein) was the most toxic, and then followed 4-hydroxy-(E)-2-nonenal and (E)-2-hexenal. While the CO(2)-photoreduction was inactivated, envelope intactness and photosynthetic electron transport activity (H(2)O --> ferredoxin) were only slightly affected. In the acrolein-treated chloroplasts, the Calvin cycle enzymes phosphoribulokinase, glyceraldehyde-3-phosphate dehydrogenase, fructose-1,6-bisphophatase, sedoheptulose-1,7-bisphosphatase, aldolase, and Rubisco were irreversibly inactivated. Acrolein treatment caused a rapid drop of the glutathione pool, prior to the inactivation of photosynthesis. GSH exogenously added to chloroplasts suppressed the acrolein-induced inactivation of photosynthesis, but ascorbic acid did not show such a protective effect. Thus, lipid peroxide-derived 2-alkenals can inhibit photosynthesis by depleting GSH in chloroplasts and then inactivating multiple enzymes in the Calvin cycle.

  14. Brown Carbon Production in Aldehyde + Ammonium Sulfate Mixtures: Effects of Formaldehyde and Amines

    NASA Astrophysics Data System (ADS)

    Powelson, M.; De Haan, D. O.

    2012-12-01

    The formation of light-absorbing 'brown carbon,' or HULIS (humic- like substances), in atmospheric aerosol has an important impact on climate. However, the precursors responsible for brown carbon formation have not been identified. Several aldehydes present in clouds (methylglyoxal, glycolaldehyde, hydroxyacetone, glyoxal, and acetaldehyde) have the potential to create brown products when reacted with ammonium sulfate or primary amines such as methylamine or glycine. The formation of light-absorbing products from these reactions was characterized as a function of cloud-relevant pH (from 3- 6) using UV-Visible spectroscopy. Of the different aldehydes teste, the largest production rates of light-absorbing compounds were observed in reactions of glycolaldehyde and methylglyoxal. Primary amines produced more light- absorbing products than ammonium sulfate at lower concentrations. The addition of formaldehyde to any reaction with other aldehydes decreased the formation of light-absorbing products, while the addition of a small amount (1:5 mole ratio) of glycine to aldehyde + ammonium sulfate reactions can increase the production of light-absorbing products. These results suggest that the presence of primary amines significantly influence atmospheric brown carbon production by aldehydes even when much greater quantities of ammonium sulfate are present.

  15. Nitrite promotes protein carbonylation and Strecker aldehyde formation in experimental fermented sausages: are both events connected?

    PubMed

    Villaverde, A; Ventanas, J; Estévez, M

    2014-12-01

    The role played by curing agents (nitrite, ascorbate) on protein oxidation and Strecker aldehyde formation is studied. To fulfill this objective, increasing concentrations of nitrite (0, 75 and 150ppm) and ascorbate (0, 250 and 500ppm) were added to sausages subjected to a 54day drying process. The concurrence of intense proteolysis, protein carbonylation and formation of Strecker aldehydes during processing of sausages suggests that α-aminoadipic semialdehyde (AAS) and γ-glutamic semialdehyde (GGS) may be implicated in the formation of Strecker aldehydes. The fact that nitrite (150ppm, ingoing amount) significantly promoted the formation of protein carbonyls at early stages of processing and the subsequent formation of Strecker aldehydes provides strength to this hypothesis. Ascorbate (125 and 250ppm) controlled the overall extent of protein carbonylation in sausages without declining the formation of Strecker aldehydes. These results may contribute to understanding the chemistry fundamentals of the positive influence of nitrite on the flavor and overall acceptability of cured muscle foods.

  16. Development of QSARs for predicting the joint effects between cyanogenic toxicants and aldehydes.

    PubMed

    Lin, Zhifen; Yin, Kedong; Shi, Ping; Wang, Liansheng; Yu, Hongxia

    2003-10-01

    Quantitative structure-activity relationship (QSAR) approaches are proposed in this study to predict the joint effects of mixture toxicity. The initial investigation studies the joint effects between cyanogenic toxicants and aldehydes to Photobacterium phosphoreum. Joint effects are found to result from the formation of a carbanion intermediate produced through the chemical interactions between cyanogenic toxicants and aldehydes. Further research indicates that the formation of carbanion intermediate is highly correlated with not only the charge of the carbon atom in the -CHO of aldehydes but also the charge of the carbon atom (C) in the carbochain of cyanogenic toxicants. The charge of the carbon atom in the -CHO of aldehydes is quantified by using the Hammett constant (sigma(p)), and then, sigma(p)-based QSAR models are proposed to describe the relationships between the joint effects and the chemical structures of the aldehydes. By using the charge of carbon atom (C) in the carbochain of cyanogenic toxicants, another QSAR model is proposed to describe the relationship between the joint effects and the chemical structures of cyanogenic toxicants.

  17. Concentration of simple aldehydes by sulfite-containing double-layer hydroxide minerals: implications for biopoesis

    NASA Technical Reports Server (NTRS)

    Pitsch, S.; Krishnamurthy, R.; Arrhenius, G.; Bada, J. L. (Principal Investigator)

    2000-01-01

    Environmental conditions play an important role in conceptual studies of prebiotically relevant chemical reactions that could have led to functional biomolecules. The necessary source compounds are likely to have been present in dilute solution, raising the question of how to achieve selective concentration and to reach activation. With the assumption of an initial 'RNA World', the questions of production, concentration, and interaction of aldehydes and aldehyde phosphates, potential precursors of sugar phosphates, come into the foreground. As a possible concentration process for simple, uncharged aldehydes, we investigated their adduct formation with sulfite ion bound in the interlayer of positively charged expanding-sheet-structure double-layer hydroxide minerals. Minerals of this type, initially with chloride as interlayer counter anion, have previously been shown to induce concentration and subsequent aldolization of aldehyde phosphates to form tetrose, pentose, and hexose phosphates. The reversible uptake of the simple aldehydes formaldehyde, glycolaldehyde, and glyceraldehyde by adduct formation with the immobilized sulfite ions is characterized by equilibrium constants of K=1.5, 9, and 11, respectively. This translates into an observable uptake at concentrations exceeding 50 mM.

  18. Characterization of Enzymes Catalyzing Transformations of Cysteine S-Conjugated Intermediates in the Lincosamide Biosynthetic Pathway.

    PubMed

    Ushimaru, Richiro; Lin, Chia-I; Sasaki, Eita; Liu, Hung-Wen

    2016-09-01

    Lincosamides such as lincomycin A, celesticetin, and Bu-2545, constitute an important group of antibiotics. These natural products are characterized by a thiooctose linked to a l-proline residue, but they differ with regards to modifications of the thioacetal moiety, the pyrrolidine ring, and the octose core. Here we report that the pyridoxal 5'-phosphate-dependent enzyme CcbF (celesticetin biosynthetic pathway) is a decarboxylating deaminase that converts a cysteine S-conjugated intermediate into an aldehyde. In contrast, the homologous enzyme LmbF (lincomycin biosynthetic pathway) catalyzes C-S bond cleavage of the same intermediate to afford a thioglycoside. We show that Ccb4 and LmbG (downstream methyltransferases) convert the aldehyde and thiol intermediates into a variety of methylated lincosamide compounds including Bu-2545. The substrates used in these studies are the β-anomers of the natural substrates. The findings not only provide insight into how the biosynthetic pathway of lincosamide antibiotics can bifurcate to generate different lincosamides, but also reveal the promiscuity of the enzymes involved. PMID:27431934

  19. A peptide nucleic acid-aminosugar conjugate targeting transactivation response element of HIV-1 RNA genome shows a high bioavailability in human cells and strongly inhibits tat-mediated transactivation of HIV-1 transcription.

    PubMed

    Das, Indrajit; Désiré, Jérôme; Manvar, Dinesh; Baussanne, Isabelle; Pandey, Virendra N; Décout, Jean-Luc

    2012-07-12

    The 6-aminoglucosamine ring of the aminoglycoside antibiotic neomycin B (ring II) was conjugated to a 16-mer peptide nucleic acid (PNA) targeting HIV-1 TAR RNA. For this purpose, we prepared the aminoglucosamine monomer 15 and attached it to the protected PNA prior to its cleavage from the solid support. We found that the resulting PNA-aminoglucosamine conjugate is stable under acidic conditions, efficiently taken up by the human cells and fairly distributed in both cytosol and nucleus without endosomal entrapment because cotreatment with endosome-disrupting agent had no effect on its cellular distribution. The conjugate displayed very high target specificity in vitro and strongly inhibited Tat mediated transactivation of HIV-1 LTR transcription in a cell culture system. The unique properties of this new class of PNA conjugate suggest it to be a potential candidate for therapeutic application.

  20. A Peptide Nucleic Acid-Aminosugar Conjugate Targeting Transactivation Response Element of HIV-1 RNA Genome Shows a High Bioavailability in Human Cells and Strongly Inhibits Tat-mediated Transactivation of HIV-1 Transcription

    PubMed Central

    Das, Indrajit; Désiré, Jérôme; Manvar, Dinesh; Baussanne, Isabelle; Pandey, Virendra N.; Décout, Jean-Luc

    2012-01-01

    The 6-aminoglucosamine ring of the aminoglycoside antibiotic neomycin B (ring II) was conjugated to a 16 mer peptide nucleic acid (PNA) targeting HIV-1 TAR RNA. For this purpose we prepared the aminoglucosamine monomer 15 and attached it to the protected PNA prior to its cleavage from the solid support. We found that the resulting PNA-aminoglucosamine conjugate is stable under acidic condition, efficiently taken up by the human cells and fairly distributed in both cytosol and nucleus without endosomal entrapment since co-treatment with endosome-disrupting agent had no effect on its cellular distribution. The conjugate displayed very high target specificity in vitro and strongly inhibited Tat mediated transactivation of HIV-1 LTR transcription in cell culture system. The unique properties of this new class of PNA conjugate suggest it to be a potential candidate for therapeutic application. PMID:22698070

  1. Hsp90 is involved in the regulation of cytosolic precursor protein abundance in tomato.

    PubMed

    Tillmann, Bodo; Röth, Sascha; Bublak, Daniela; Sommer, Manuel; Stelzer, Ernst H K; Scharf, Klaus-Dieter; Schleiff, Enrico

    2015-02-01

    Cytosolic chaperones are involved in the regulation of cellular protein homeostasis in general. Members of the families of heat stress proteins 70 (Hsp70) and 90 (Hsp90) assist the transport of preproteins to organelles such as chloroplasts or mitochondria. In addition, Hsp70 was described to be involved in the degradation of chloroplast preproteins that accumulate in the cytosol. Because a similar function has not been established for Hsp90, we analyzed the influences of Hsp90 and Hsp70 on the protein abundance in the cellular context using an in vivo system based on mesophyll protoplasts. We observed a differential behavior of preproteins with respect to the cytosolic chaperone-dependent regulation. Some preproteins such as pOE33 show a high dependence on Hsp90, whereas the abundance of preproteins such as pSSU is more strongly dependent on Hsp70. The E3 ligase, C-terminus of Hsp70-interacting protein (Chip), appears to have a more general role in the control of cytosolic protein abundance. We discuss why the different reaction modes are comparable with the cytosolic unfolded protein response. PMID:25619681

  2. Reversal of Cytosolic One-Carbon Flux Compensates for Loss of the Mitochondrial Folate Pathway.

    PubMed

    Ducker, Gregory S; Chen, Li; Morscher, Raphael J; Ghergurovich, Jonathan M; Esposito, Mark; Teng, Xin; Kang, Yibin; Rabinowitz, Joshua D

    2016-06-14

    One-carbon (1C) units for purine and thymidine synthesis can be generated from serine by cytosolic or mitochondrial folate metabolism. The mitochondrial 1C pathway is consistently overexpressed in cancer. Here, we show that most but not all proliferating mammalian cell lines use the mitochondrial pathway as the default for making 1C units. Clustered regularly interspaced short palindromic repeats (CRISPR)-mediated mitochondrial pathway knockout activates cytosolic 1C-unit production. This reversal in cytosolic flux is triggered by depletion of a single metabolite, 10-formyl-tetrahydrofolate (10-formyl-THF), and enables rapid cell growth in nutrient-replete conditions. Loss of the mitochondrial pathway, however, renders cells dependent on extracellular serine to make 1C units and on extracellular glycine to make glutathione. HCT-116 colon cancer xenografts lacking mitochondrial 1C pathway activity generate the 1C units required for growth by cytosolic serine catabolism. Loss of both pathways precludes xenograft formation. Thus, either mitochondrial or cytosolic 1C metabolism can support tumorigenesis, with the mitochondrial pathway required in nutrient-poor conditions. PMID:27211901

  3. Stimulation of hormone-responsive adenylate cyclase activity by a factor present in the cell cytosol.

    PubMed Central

    MacNeil, S; Crawford, A; Amirrasooli, H; Johnson, S; Pollock, A; Ollis, C; Tomlinson, S

    1980-01-01

    1. Homogenates of whole tissues were shown to contain both intracellular and extracellular factors that affected particulate adenylate cyclase activity in vitro. Factors present in the extracellular fluids produced an inhibition of basal, hormone- and fluoride-stimulated enzyme activity but factors present in the cell cytosol increased hormone-stimulated activity with relatively little effect on basal or fluoride-stimulated enzyme activity. 2. The existence of this cytosol factor or factors was investigated using freshly isolated human platelets, freshly isolated rat hepatocytes, and cultured cells derived from rat osteogenic sarcoma, rat calvaria, mouse melanoma, pig aortic endothelium, human articular cartilage chondrocytes and human bronchial carcinoma (BEN) cells. 3. The stimulation of the hormone response by the cytosol factor ranged from 60 to 890% depending on the tissue of origin of the adenylate cyclase. 4. In each case the behaviour of the factor was similar to the action of GTP on that particular adenylate cyclase preparation. 5. No evidence of tissue or species specificity was found, as cytosols stimulated adenylate cyclase from their own and unrelated tissues to the same degree. 6. In the human platelet, the inclusion of the cytosol in the assay of adenylate cyclase increased the rate of enzyme activity in response to stimulation by prostaglandin E1 without affecting the amount of prostaglandin E1 required for half-maximal stimulation or the characteristics of enzyme activation by prostaglandin E. PMID:7396869

  4. Differential effects of polyamine on the cytosolic and mitochondrial NADP-isocitrate dehydrogenases.

    PubMed

    Murakami, Keiko; Haneda, Miyako; Iwata, Shouko; Yoshino, Masataka

    2012-01-01

    Two isozymes of NADP-dependent isocitrate dehydrogenases (EC 1.1.1.42) exist in mammalian tissues: mitochondrial (ICD1) and cytosolic (ICD2). Effects of polyamines such as spermine, spermidine, and putrescine on the cytosolic and mitochondrial NADP-isocitrate dehydrogenases were analyzed kinetically. Spermine activated ICD2, the cytosolic NADP-isocitrate dehydrogenase from rat liver with the increase in the maximal velocity and the decrease in the affinity for the substrates isocitrate and NADP. The activating action of spermine can be explained by "the uncompetitive effect," and the dissociation constant of spermine for the enzyme-substrate complex was determined to be 1.68 mM. Spermidine and putrescine showed little or no effect. ICD1, the mitochondrial form of NADP-isocitrate dehydrogenase from rat and porcine heart was inhibited by spermine effectively, and by spermidine and putrescine to a lesser extent. Spermine inhibited the enzyme competitively with respect to NADP, and noncompetitively with respect to isocitrate. K(i) value of the enzyme for spermine was 1.3 mM. These results suggest that activation by spermine of cytosolic NADP-isocitrate dehydrogenase can enhance the antioxidant activity by regeneration of GSH, and further is responsible for the stimulation of lipid biosynthesis in cytosol. Spermine may contribute to NADPH supply by enhancing transhydrogenase (EC1.6.1.2) activity through the spermine-dependent activation of Ca(2+) -incorporation to mitochondria.

  5. Cytosolic Ca(2+) Signals Enhance the Vacuolar Ion Conductivity of Bulging Arabidopsis Root Hair Cells.

    PubMed

    Wang, Yi; Dindas, Julian; Rienmüller, Florian; Krebs, Melanie; Waadt, Rainer; Schumacher, Karin; Wu, Wei-Hua; Hedrich, Rainer; Roelfsema, M Rob G

    2015-11-01

    Plant cell expansion depends on the uptake of solutes across the plasma membrane and their storage within the vacuole. In contrast to the well-studied plasma membrane, little is known about the regulation of ion transport at the vacuolar membrane. We therefore established an experimental approach to study vacuolar ion transport in intact Arabidopsis root cells, with multi-barreled microelectrodes. The subcellular position of electrodes was detected by imaging current-injected fluorescent dyes. Comparison of measurements with electrodes in the cytosol and vacuole revealed an average vacuolar membrane potential of -31 mV. Voltage clamp recordings of single vacuoles resolved the activity of voltage-independent and slowly deactivating channels. In bulging root hairs that express the Ca(2+) sensor R-GECO1, rapid elevation of the cytosolic Ca(2+) concentration was observed, after impalement with microelectrodes, or injection of the Ca(2+) chelator BAPTA. Elevation of the cytosolic Ca(2+) level stimulated the activity of voltage-independent channels in the vacuolar membrane. Likewise, the vacuolar ion conductance was enhanced during a sudden increase of the cytosolic Ca(2+) level in cells injected with fluorescent Ca(2+) indicator FURA-2. These data thus show that cytosolic Ca(2+) signals can rapidly activate vacuolar ion channels, which may prevent rupture of the vacuolar membrane, when facing mechanical forces. PMID:26232520

  6. TRIM21: a cytosolic Fc receptor with broad antibody isotype specificity

    PubMed Central

    Foss, Stian; Watkinson, Ruth; Sandlie, Inger; James, Leo C; Andersen, Jan Terje

    2015-01-01

    Antibodies are key molecules in the fight against infections. Although previously thought to mediate protection solely in the extracellular environment, recent research has revealed that antibody-mediated protection extends to the cytosolic compartment of cells. This postentry viral defense mechanism requires binding of the antibody to a cytosolic Fc receptor named tripartite motif containing 21 (TRIM21). In contrast to other Fc receptors, TRIM21 shows remarkably broad isotype specificity as it does not only bind IgG but also IgM and IgA. When viral pathogens coated with these antibody isotypes enter the cytosol, TRIM21 is rapidly recruited and efficient neutralization occurs before the virus has had the time to replicate. In addition, inflammatory signaling is induced. As such, TRIM21 acts as a cytosolic sensor that engages antibodies that have failed to protect against infection in the extracellular environment. Here, we summarize our current understanding of how TRIM21 orchestrates humoral immunity in the cytosolic environment. PMID:26497531

  7. Role of cytosol in the stimulation of RNA transport in vitro during cardiac hypertrophy in rats.

    PubMed Central

    Subramaniam, A; Thirunavukkarasu, M; Rajamanickam, C

    1990-01-01

    The 100,000 g supernatant isolated from hypertrophic hearts on fractionation by (NH4)2SO4 and DEAE-cellulose chromatography showed an enhanced RNA-transport activity when incubated with isolated nuclei from sham-operated hearts in vitro. Proteins of Mr 73,000, 68,000, 43,000 and 32,000 are enriched in the DEAE-cellulose fractions exhibiting maximal transport activity, and they are phosphorylatable. Pretreatment of the cytosol with antibodies to the Mr-68,000 and -32,000 proteins decreases the transport activity of the cytosol from 14% to 4.25%. Proteins of Mr 73,000, 68,000, 43,000 and 32,000 are translocated from the cytosol to the nuclear envelope under conditions of RNA transport in vitro. Our results here suggest that at least two of these proteins, those of Mr 68,000 and 32,000, play an indispensible role in the nucleocytoplasmic RNA transport in vitro. By making use of a specific myosin heavy-chain B-gene probe and hybridization, we have also shown the effect of cytosol on the transport of myosin heavy-chain mRNA from nucleus to cytosol. Images Fig. 2. Fig. 4. Fig. 5. Fig. 6. Fig. 8. PMID:1691634

  8. Efficient cytosolic delivery mediated by polymersomes facilely prepared from a degradable, amphiphilic, and amphoteric copolymer

    NASA Astrophysics Data System (ADS)

    Huang, Zhonghui; Teng, Wei; Liu, Longshan; Wang, Lichun; Wang, Qinmei; Dong, Yugang

    2013-07-01

    To solve problems in polymersome preparation caused by liposolubility of copolymers and to improve the cytosolic delivery efficiency of polymersomes to drugs, a lipopolysaccharide-amine (LPSA) copolymer with amphotericity and amphiphilicity is developed. LPSA contains two hydrophilic oppositely charged blocks (anionic oxidized alginate (OA), cationic polyethyleneimine (PEI 1.8k)) and one hydrophobic block (cholesteryl), where OA is the backbone and cholesteryl-grafted PEI is the side chain. The two hydrophilic blocks first guarantee that LPSA will dissolve in water, and then help polymersome formation via electrostatic interactions to generate water insoluble interpolyelectrolyte complexes, which supplement the hydrophobic part to reach the right hydrophilicity/hydrophobicity ratio, and thus realize a one-step self-assembly of polymersomes in water. Our results show LPSA nanopolymersomes (LNPs) have low cytotoxicity and degradability, and an excellent ability to enter cells. TEM observation demonstrates that LNPs are entrapped in endosomes after endocytosis, and are then released to cytosols because of their strong endosomal escape capacity. As an example of cytosolic delivery to bioactive molecules, pDNA is delivered in mesenchymal stem cells, and more than 95% of cells express a large target protein, indicating that LNPs have high cytosolic delivery efficiency. Our study provides a novel, easy, and universal method to design copolymers for the preparation of polymersomes as efficient cytosolic delivery nanocarriers.

  9. Periportal zonation of the cytosolic acetyl-CoA synthetase of male rat liver.

    PubMed

    Knudsen, C T; Immerdal, L; Grunnet, N; Quistorff, B

    1992-02-15

    Several important metabolic functions of the mammalian liver have been shown to be located in zones with respect to the complex microcirculation of the organ. The zonal distribution of the cytosolic component of the acetyl-CoA synthetase activity has been investigated using the dual-digitonin-pulse-perfusion technique, which allows highly zone-selective sampling of cytosol from the periportal and perivenous zone of rat liver. Approximately 80% of the cytosolic enzymes are eluted from the hepatocytes in the periportal and perivenous sub-zones affected by digitonin, while less than 1% of the glutamate dehydrogenase activity (a marker enzyme of the mitochondrial compartment) is eluted. A twofold higher activity of the cytosolic form of acetyl-CoA synthetase is found in the periportal zone compared to the perivenous zone in fed male rats. Following a fasting/refeeding transition, this activity gradient is abolished in a manner similar to that observed for the enzyme acetyl-CoA carboxylase. Since the latter enzyme is utilizing the product of acetyl-CoA synthetase, acetyl-CoA, the similarity in the observed regulation suggests a functional coupling between cytosolic acetate activation and fatty-acid synthesis.

  10. Regulation of Ubiquitin-Proteasome System–mediated Degradation by Cytosolic Stress

    PubMed Central

    Kelly, Sean M.; VanSlyke, Judy K.

    2007-01-01

    ER-associated, ubiquitin-proteasome system (UPS)-mediated degradation of the wild-type (WT) gap junction protein connexin32 (Cx32) is inhibited by mild forms of cytosolic stress at a step before its dislocation into the cytosol. We show that the same conditions (a 30-min, 42°C heat shock or oxidative stress induced by arsenite) also reduce the endoplasmic reticulum (ER)-associated turnover of disease-causing mutants of Cx32 and the cystic fibrosis transmembrane conductance regulator (CFTR), as well as that of WT CFTR and unassembled Ig light chain. Stress-stabilized WT Cx32 and CFTR, but not the mutant/unassembled proteins examined, could traverse the secretory pathway. Heat shock also slowed the otherwise rapid UPS-mediated turnover of the cytosolic proteins myoD and GFPu, but not the degradation of an ubiquitination-independent construct (GFP-ODC) closely related to the latter. Analysis of mutant Cx32 from cells exposed to proteasome inhibitors and/or cytosolic stress indicated that stress reduces degradation at the level of substrate polyubiquitination. These findings reveal a new link between the cytosolic stress-induced heat shock response, ER-associated degradation, and polyubiquitination. Stress-denatured proteins may titer a limiting component of the ubiquitination machinery away from pre-existing UPS substrates, thereby sparing the latter from degradation. PMID:17699585

  11. Binding proteins for growth hormone and prolactin in rabbit kidney cytosol

    SciTech Connect

    Herington, A.C.; Stevenson, J.L.; Ymer, S.I. )

    1988-09-01

    Two soluble, receptor-like binding proteins with apparent somatotrophic (growth hormone (GH)) and lactogenic (prolactin (PRL)) specificities, respectively, and that are present in rabbit kidney cytosol have now been examined in more detail using specific GH receptor and PRL receptor monoclonal antibodies (MAb). Gel chromatography of {sup 125}I-labeled human GH ({sup 125}I-hGH) kidney cytosol complexes in the absence of these MAbs revealed two specifically bound regions of radioactivity at molecular weights (MW) of {approximately}120,000 and {approximately}60,000, which are similar in size to complexes formed by the native GH receptor of rabbit liver cytosol and the PRL receptor of mammary gland. Co-incubation with GH-receptor MAb inhibited {sup 125}I-hGH binding only to the higher MW (120,000) species, whereas the PRL-receptor MAb inhibited only the lower MW (60,000) species, thus establishing definitively the hormonal specificities of the two binding proteins. The presence of both GH- and PRL-specific binding subunits in cytosol was confirmed using covalent cross-linking techniques. No GH binding protein was detected in kidney membranes. The presence of naturally soluble, receptor-like binding proteins for GH and PRL in kidney cytosol preparations raises the possibility of their playing a role in the intracellular regulation of kidney function and/or metabolism.

  12. Cytosolic Ca(2+) Signals Enhance the Vacuolar Ion Conductivity of Bulging Arabidopsis Root Hair Cells.

    PubMed

    Wang, Yi; Dindas, Julian; Rienmüller, Florian; Krebs, Melanie; Waadt, Rainer; Schumacher, Karin; Wu, Wei-Hua; Hedrich, Rainer; Roelfsema, M Rob G

    2015-11-01

    Plant cell expansion depends on the uptake of solutes across the plasma membrane and their storage within the vacuole. In contrast to the well-studied plasma membrane, little is known about the regulation of ion transport at the vacuolar membrane. We therefore established an experimental approach to study vacuolar ion transport in intact Arabidopsis root cells, with multi-barreled microelectrodes. The subcellular position of electrodes was detected by imaging current-injected fluorescent dyes. Comparison of measurements with electrodes in the cytosol and vacuole revealed an average vacuolar membrane potential of -31 mV. Voltage clamp recordings of single vacuoles resolved the activity of voltage-independent and slowly deactivating channels. In bulging root hairs that express the Ca(2+) sensor R-GECO1, rapid elevation of the cytosolic Ca(2+) concentration was observed, after impalement with microelectrodes, or injection of the Ca(2+) chelator BAPTA. Elevation of the cytosolic Ca(2+) level stimulated the activity of voltage-independent channels in the vacuolar membrane. Likewise, the vacuolar ion conductance was enhanced during a sudden increase of the cytosolic Ca(2+) level in cells injected with fluorescent Ca(2+) indicator FURA-2. These data thus show that cytosolic Ca(2+) signals can rapidly activate vacuolar ion channels, which may prevent rupture of the vacuolar membrane, when facing mechanical forces.

  13. A fragment of anthrax lethal factor delivers proteins to the cytosol without requiring protective antigen

    PubMed Central

    Kushner, Nicholas; Zhang, Dong; Touzjian, Neal; Essex, Max; Lieberman, Judy; Lu, Yichen

    2003-01-01

    Anthrax protective antigen (PA) is a 735-aa polypeptide that facilitates the exit of anthrax lethal factor (LF) from the endosome to the cytosol where the toxin acts. We recently found, however, that a fusion protein of the detoxified N-terminal domain of lethal factor (LFn) with a foreign peptide could induce CD8 T cell immune responses in the absence of PA. Because CD8 T cells recognize peptides derived from proteins degraded in the cytosol, this result suggests that lethal factor may be capable of entering the cytosol independently of PA. To investigate this further, the intracellular trafficking of an LFn-enhanced green fluorescent protein fusion protein (LFn-GFP) in the presence or absence of PA was examined by using confocal microscopy. LFn-GFP is able to enter the cytosol without PA. Moreover, it efficiently colocalizes with the proteosome 20s subunit, which degrades proteins into peptides for presentation to CD8 T cells by the MHC class I pathway. We further demonstrate that in the presence of an immune adjuvant LFn fusion protein without PA is able to effectively elicit anti-HIV cytotoxic T lymphocyte in inbred mice. These results indicate that LFn may be used without PA in a protein vaccine as a carrier to deliver antigens into the cytosol for efficient induction of T lymphocyte responses. Furthermore, these results enable us to propose a modified molecular mechanism of anthrax lethal toxin. PMID:12740437

  14. The role of cytosolic proteins in the insertion of tail-anchored proteins into phospholipid bilayers.

    PubMed

    Colombo, Sara F; Longhi, Renato; Borgese, Nica

    2009-07-15

    Tail-anchored (TA) proteins are membrane proteins that contain an N-terminal domain exposed to the cytosol and a single transmembrane segment near the C-terminus followed by few or no polar residues. TA proteins with a mildly hydrophobic transmembrane domain, such as cytochrome b5 (b5), are able to insert post-translationally into pure lipid vesicles without assistance from membrane proteins. Here, we investigated whether any cytosolic proteins are needed to maintain b5 in a competent state for transmembrane integration. Using b5 constructs translated in vitro or produced in bacteria, we demonstrate that cytosolic proteins are neither necessary nor facilitatory for the unassisted translocation of b5. Furthermore, we demonstrate that no cytosolic protein is involved in the translocation of a C-terminal domain of 85 residues appended to the transmembrane domain of b5. Nevertheless, b5 does bind cytosolic proteins, and in their presence but not in their absence, its insertion into liposomes is inhibited by the thiol oxidant diamide and the alkylating agent N-ethylmaleimide. The effect of diamide is also observed in living cells. Thus, the specific in vivo targeting of b5 might be achieved by interaction with redox-sensitive targeting factors that hinder its nonspecific insertion into any permissive bilayer.

  15. Stability Enhancing N-Terminal PEGylation of Oxytocin Exploiting Different Polymer Architectures and Conjugation Approaches.

    PubMed

    Collins, Jennifer; Kempe, Kristian; Wilson, Paul; Blindauer, Claudia A; McIntosh, Michelle P; Davis, Thomas P; Whittaker, Michael R; Haddleton, David M

    2016-08-01

    Oxytocin, a cyclic nine amino acid neurohypophyseal hormone therapeutic, is effectively used in the control of postpartum hemorrhaging (PPH) and is on the WHO List of Essential Medicines. However, oxytocin has limited shelf life stability in aqueous solutions, particularly at temperatures in excess of 25 °C and injectable aqueous oxytocin formulations require refrigeration (<8 °C). This is particularly problematic in the hot climates often found in many developing countries where daytime temperatures can exceed 40 °C and where reliable cold-chain storage is not always achievable. The purpose of this study was to develop N-terminal amine targeted PEGylation strategies utilizing both linear PEG and polyPEG "comb" polymers as an effective method for stabilizing solution formulations of this peptide for prolonged storage in the absence of efficient cold-chain storage. The conjugation chemistries investigated herein include irreversible amine targeted conjugation methods utilizing NHS ester and aldehyde reductive amination chemistry. Additionally, one reversible conjugation method using a Schiff base approach was explored to allow for the release of the native peptide, thus, ensuring that biological activity remains unaffected. The reversibility of this approach was investigated for the different polymer architectures, alongside a nonpolymer oxytocin analogue to monitor how pH can tune native peptide release. Elevated temperature degradation studies of the polymer conjugates were evaluated to assess the stability of the PEGylated analogues in comparison to the native peptide in aqueous formulations to mimic storage conditions in developing nations and regions where storage under appropriate conditions is challenging. PMID:27419537

  16. Highly enantioselective reductive cyclization of acetylenic aldehydes via rhodium catalyzed asymmetric hydrogenation.

    PubMed

    Rhee, Jong Uk; Krische, Michael J

    2006-08-23

    Catalytic hydrogenation of acetylenic aldehydes 1a-12a using chirally modified cationic rhodium catalysts enables highly enantioselective reductive cyclization to afford cyclic allylic alcohols 1b-12b. Using an achiral hydrogenation catalyst, the chiral racemic acetylenic aldehydes 13a-15a engage in highly syn-diastereoselective reductive cyclizations to afford cyclic allylic alcohols 13b-15b. Ozonolysis of cyclization products 7b and 9b allows access to optically enriched alpha-hydroxy ketones 7c and 9c. Reductive cyclization of enyne 7a under a deuterium atmosphere provides the monodeuterated product deuterio-7b, consistent with a catalytic mechanism involving alkyne-carbonyl oxidative coupling followed by hydrogenolytic cleavage of the resulting oxametallacycle. These hydrogen-mediated transformations represent the first examples of the enantioselective reductive cyclization of acetylenic aldehydes. PMID:16910650

  17. Catalytic production of methyl acrylates by gold-mediated cross coupling of unsaturated aldehydes with methanol

    NASA Astrophysics Data System (ADS)

    Karakalos, Stavros; Zugic, Branko; Stowers, Kara J.; Biener, Monika M.; Biener, Juergen; Friend, Cynthia M.; Madix, Robert J.

    2016-10-01

    Modern methods of esterification, one of the most important reactions in organic synthesis, are reaching their limits, as far as waste and expense are concerned. Novel chemical approaches to ester formation are therefore of importance. Here we report a simple procedure free of caustic reagents or byproducts for the facile direct oxidative methyl esterification of aldehydes over nanoporous Au catalysts. Complementary model studies on single crystal gold surfaces establish the fundamental reactions involved. We find that methanol more readily reacts with adsorbed active oxygen than do the aldehydes, but that once the aldehydes do react, they form strongly-bound acrylates that block reactive sites and decrease the yields of acrylic esters under steady flow conditions at 420 K. Significant improvements in yield can be achieved by operating at higher temperatures, which render the site-blocking acrylates unstable.

  18. Target-Specific Capture of Environmentally Relevant Gaseous Aldehydes and Carboxylic Acids with Functional Nanoparticles.

    PubMed

    Campbell, McKenzie L; Guerra, Fernanda D; Dhulekar, Jhilmil; Alexis, Frank; Whitehead, Daniel C

    2015-10-12

    Aldehyde and carboxylic acid volatile organic compounds (VOCs) present significant environmental concern due to their prevalence in the atmosphere. We developed biodegradable functional nanoparticles comprised of poly(d,l-lactic acid)-poly(ethylene glycol)-poly(ethyleneimine) (PDLLA-PEG-PEI) block co-polymers that capture these VOCs by chemical reaction. Polymeric nanoparticles (NPs) preparation involved nanoprecipitation and surface functionalization with branched PEI. The PDLLA-PEG-PEI NPs were characterized by using TGA, IR, (1) H NMR, elemental analysis, and TEM. The materials feature 1°, 2°, and 3° amines on their surface, capable of capturing aldehydes and carboxylic acids from gaseous mixtures. Aldehydes were captured by a condensation reaction forming imines, whereas carboxylic acids were captured by acid/base reaction. These materials reacted selectively with target contaminants obviating off-target binding when challenged by other VOCs with orthogonal reactivity. The NPs outperformed conventional activated carbon sorbents.

  19. A molecularly defined iron-catalyst for the selective hydrogenation of α,β-unsaturated aldehydes.

    PubMed

    Wienhöfer, Gerrit; Westerhaus, Felix A; Junge, Kathrin; Ludwig, Ralf; Beller, Matthias

    2013-06-10

    A selective iron-based catalyst system for the hydrogenation of α,β-unsaturated aldehydes to allylic alcohols is presented. Applying the defined iron-tetraphos complex [FeF(L)][BF4] (L = P(PhPPh2)3) in the presence of trifluoroacetic acid a broad range of aldehydes are reduced in high yields using low catalyst loadings (0.05-1 mol %). Excellent chemoselectivity for the reduction of aldehydes in the presence of other reducible moieties, for example, ketones, olefins, esters, etc. is achieved. Based on the in situ detected hydride species [FeH(H2)(L)](+) a catalytic cycle is proposed that is supported by computational calculations. PMID:23649662

  20. Effects of light and copper ions on volatile aldehydes of milk and milk fractions

    SciTech Connect

    Jeno, W.; Bassette, R.; Crang, R.E.

    1988-09-01

    Raw, laboratory-pasteurized and plant-pasteurized homogenized milks were exposed to copper ions (5 ppm), to sunlight or fluorescent light and the effects determined on the composition of volatile aldehydes. The greatest change due to copper treatment was an increase in n-hexanal; acetaldehyde showed the least response in each of the sources of milk. The responses were similar from all three sources of milk with laboratory-pasteurized milk samples showing the greatest responses for each aldehyde analyzed. Similar milk samples exposed to sunlight also showed an increase in volatile aldehydes from all milk sources but with the greatest response being acetaldehyde and n-pentanal components. The milk fraction most susceptible to changes in the presence of light was neutralized whey, whereas resuspended cream was most susceptible to copper exposure. Overall, dialyzed whey appeared to be influenced more than other milk fractions by both light and copper ions.

  1. Palladium and platinum catalyzed addition of allylstannanes to aldehydes and imines

    SciTech Connect

    Nakamura, Hiroyuki; Yamamoto, Yoshinori

    1995-12-31

    The reaction of allylstannanes with aldehydes in THF was catalyzed by Pd(II) or Pt(II) complexes (10 mole %) either at room temperature or at reflux, giving the corresponding homoallyl alcohols in high to good yields. Among the catalysts examined, PtCl{sub 2}(PPh{sub 3}){sub 2} gave the best result. Aromatic, aliphatic, and {alpha},{beta}-unsaturated aldehydes can be utilized and even cyclohexanone undergoes the allylation reaction. Allyl and methallyltributylstannane reacted very smoothly. Crotyltributylstannane also reacted with aldehydes to give the branched homoallyl alcohols in good yields, but the reaction speed was slower than that of allylstannane. Detailed mechanistic studies of the Pd(II) catalyzed allylation, using NMR spectra, revealed that bis-{pi}-allyl palladium 5 is a key intermediate for the catalytic cycle and it exhibits nucleophilic reactivity.

  2. A molecularly defined iron-catalyst for the selective hydrogenation of α,β-unsaturated aldehydes.

    PubMed

    Wienhöfer, Gerrit; Westerhaus, Felix A; Junge, Kathrin; Ludwig, Ralf; Beller, Matthias

    2013-06-10

    A selective iron-based catalyst system for the hydrogenation of α,β-unsaturated aldehydes to allylic alcohols is presented. Applying the defined iron-tetraphos complex [FeF(L)][BF4] (L = P(PhPPh2)3) in the presence of trifluoroacetic acid a broad range of aldehydes are reduced in high yields using low catalyst loadings (0.05-1 mol %). Excellent chemoselectivity for the reduction of aldehydes in the presence of other reducible moieties, for example, ketones, olefins, esters, etc. is achieved. Based on the in situ detected hydride species [FeH(H2)(L)](+) a catalytic cycle is proposed that is supported by computational calculations.

  3. Evolution of volatile aldehydes in Iberian ham matured under different processing conditions.

    PubMed

    Martín, L; Timón, M L; Petrón, M J; Ventanas, J; Antequera, T

    2000-04-01

    To evaluate the influence of the Iberian ham processing conditions in the evolution of volatile aldehydes, 35 hams were processed in two plants following different conditions of relative humidity and temperature. For this, free fatty acids, peroxide values and volatile aldehydes were quantified in the hams. The highest increases in free fatty acids were noted during the drying stage in both processing plants. The drying period also revealed the greatest increase in peroxide values, where the highest values were in those hams processed at higher temperatures. The temperature during post-salting and drying had a marked influence on the formation of volatile aldehydes, being responsible for the differences in volatile compounds of matured hams.

  4. Magnesium Sensitizes Slow Vacuolar Channels to Physiological Cytosolic Calcium and Inhibits Fast Vacuolar Channels in Fava Bean Guard Cell Vacuoles.

    PubMed

    Pei; Ward; Schroeder

    1999-11-01

    Vacuolar ion channels in guard cells play important roles during stomatal movement and are regulated by many factors including Ca(2+), calmodulin, protein kinases, and phosphatases. We report that physiological cytosolic and luminal Mg(2+) levels strongly regulate vacuolar ion channels in fava bean (Vicia faba) guard cells. Luminal Mg(2+) inhibited fast vacuolar (FV) currents with a K(i) of approximately 0.23 mM in a voltage-dependent manner at positive potentials on the cytoplasmic side. Cytosolic Mg(2+) at 1 mM also inhibited FV currents. Furthermore, in the absence of cytosolic Mg(2+), cytosolic Ca(2+) at less than 10 µM did not activate slow vacuolar (SV) currents. However, when cytosolic Mg(2+) was present, submicromolar concentrations of cytosolic Ca(2+) activated SV currents with a K(d) of approximately 227 nM, suggesting a synergistic Mg(2+)-Ca(2+) effect. The activation potential of SV currents was shifted toward physiological potentials in the presence of cytosolic Mg(2+) concentrations. The direction of SV currents could also be changed from outward to both outward and inward currents. Our data predict a model for SV channel regulation, including a cytosolic binding site for Ca(2+) with an affinity in the submicromolar range and a cytosolic low-affinity Mg(2+)-Ca(2+) binding site. SV channels are predicted to contain a third binding site on the vacuolar luminal side, which binds Ca(2+) and is inhibitory. In conclusion, cytosolic Mg(2+) sensitizes SV channels to physiological cytosolic Ca(2+) elevations. Furthermore, we propose that cytosolic and vacuolar Mg(2+) concentrations ensure that FV channels do not function as a continuous vacuolar K(+) leak, which would prohibit stomatal opening.

  5. Magnesium Sensitizes Slow Vacuolar Channels to Physiological Cytosolic Calcium and Inhibits Fast Vacuolar Channels in Fava Bean Guard Cell Vacuoles.

    PubMed

    Pei; Ward; Schroeder

    1999-11-01

    Vacuolar ion channels in guard cells play important roles during stomatal movement and are regulated by many factors including Ca(2+), calmodulin, protein kinases, and phosphatases. We report that physiological cytosolic and luminal Mg(2+) levels strongly regulate vacuolar ion channels in fava bean (Vicia faba) guard cells. Luminal Mg(2+) inhibited fast vacuolar (FV) currents with a K(i) of approximately 0.23 mM in a voltage-dependent manner at positive potentials on the cytoplasmic side. Cytosolic Mg(2+) at 1 mM also inhibited FV currents. Furthermore, in the absence of cytosolic Mg(2+), cytosolic Ca(2+) at less than 10 µM did not activate slow vacuolar (SV) currents. However, when cytosolic Mg(2+) was present, submicromolar concentrations of cytosolic Ca(2+) activated SV currents with a K(d) of approximately 227 nM, suggesting a synergistic Mg(2+)-Ca(2+) effect. The activation potential of SV currents was shifted toward physiological potentials in the presence of cytosolic Mg(2+) concentrations. The direction of SV currents could also be changed from outward to both outward and inward currents. Our data predict a model for SV channel regulation, including a cytosolic binding site for Ca(2+) with an affinity in the submicromolar range and a cytosolic low-affinity Mg(2+)-Ca(2+) binding site. SV channels are predicted to contain a third binding site on the vacuolar luminal side, which binds Ca(2+) and is inhibitory. In conclusion, cytosolic Mg(2+) sensitizes SV channels to physiological cytosolic Ca(2+) elevations. Furthermore, we propose that cytosolic and vacuolar Mg(2+) concentrations ensure that FV channels do not function as a continuous vacuolar K(+) leak, which would prohibit stomatal opening. PMID:10557247

  6. The Cytosolic pH of Individual Saccharomyces cerevisiae Cells Is a Key Factor in Acetic Acid Tolerance.

    PubMed

    Fernández-Niño, Miguel; Marquina, Maribel; Swinnen, Steve; Rodríguez-Porrata, Boris; Nevoigt, Elke; Ariño, Joaquín

    2015-11-01

    It was shown recently that individual cells of an isogenic Saccharomyces cerevisiae population show variability in acetic acid tolerance, and this variability affects the quantitative manifestation of the trait at the population level. In the current study, we investigated whether cell-to-cell variability in acetic acid tolerance could be explained by the observed differences in the cytosolic pHs of individual cells immediately before exposure to the acid. Results obtained with cells of the strain CEN.PK113-7D in synthetic medium containing 96 mM acetic acid (pH 4.5) showed a direct correlation between the initial cytosolic pH and the cytosolic pH drop after exposure to the acid. Moreover, only cells with a low initial cytosolic pH, which experienced a less severe drop in cytosolic pH, were able to proliferate. A similar correlation between initial cytosolic pH and cytosolic pH drop was also observed in the more acid-tolerant strain MUCL 11987-9. Interestingly, a fraction of cells in the MUCL 11987-9 population showed initial cytosolic pH values below the minimal cytosolic pH detected in cells of the strain CEN.PK113-7D; consequently, these cells experienced less severe drops in cytosolic pH. Although this might explain in part the difference between the two strains with regard to the number of cells that resumed proliferation, it was observed that all cells from strain MUCL 11987-9 were able to proliferate, independently of their initial cytosolic pH. Therefore, other factors must also be involved in the greater ability of MUCL 11987-9 cells to endure strong drops in cytosolic pH.

  7. Metal exposures to native populations of the caddisfly Hydropsyche (Trichoptera: Hydropsychidae) determined from cytosolic and whole body metal concentrations

    USGS Publications Warehouse

    Cain, D.J.; Luoma, S.N.

    1998-01-01

    Metal concentrations of the soluble fraction of the cytoplasm (cytosol) and the whole body were determined in the caddisfly Hydropsyche spp. (Trichoptera). Metal accumulation in the cytosol and the whole body were compared in samples collected along 380 kms of a contamination gradient in the Clark Fork river in four consecutive years (1992-1995), and from a contaminated tributary (Flint Creek). Samples from the contaminated sites were compared to an uncontaminated tributary (Blackfoot River). Relations between cytosolic metal concentration and cytosolic protein (used as a general biomarker of protein metabolism) also were examined in 1994 and 1995. Relative to whole body concentrations, cytosolic metal concentrations varied among metals and years. Spatial patterns in whole body and cytosolic Cd, Cu and Pb concentrations were qualitatively similar each year, and these concentrations generally corresponded to contamination levels measured in bed sediments. The proportions of metals recovered in the cytosol of ranged from 12 to 64% for Cd and Cu and from 2 to 38% for Pb. Zinc in the whole body also was consistent with contamination levels, but cytosolic Zn concentrations increased only at the highest whole body Zn concentrations. As a result, the proportion of Zn recovered in the cytosol ranged from 16 to 63% and tended to be inversely related to whole body Zn concentrations. The proportions of cytosolic metals varied significantly among years and, as a result, interannual differences in metal concentrations were greater in the cytosol than in the whole body. The results demonstrated that Hydropsyche in the river were chronically exposed to biologically available metals. Some features of this exposure were not evident from whole body concentrations. In general, protein levels did not correspond to cytosolic metal concentrations. A variety of environmental factors could interact with metal exposures to produce complex responses in protein metabolism. Systematic study

  8. Occupational Exposure to Volatile Organic Compounds and Aldehydes in the U.S. Trucking Industry

    PubMed Central

    DAVIS, M. E.; BLICHARZ, A. P.; HART, J. E.; LADEN, F.; GARSHICK, E.; SMITH, T. J.

    2008-01-01

    Diesel exhaust is a complex chemical mixture that has been linked to lung cancer mortality in a number of epidemiologic studies. However, the dose–response relationship remains largely undefined, and the specific components responsible for carcinogenicity have not been identified. Although previous focus has been on the particulate phase, diesel exhaust includes a vapor phase of numerous volatile organic compounds (VOCs) and aldehydes that are either known or suspected carcinogens, such as 1,3-butadiene, benzene, and formaldehyde. However, there are relatively few studies that quantify exposure to VOCs and aldehydes in diesel-heavy and other exhaust-related microenvironments. As part of a nationwide assessment of exposure to diesel exhaust in the trucking industry, we collected measurements of VOCs and aldehydes at 15 different U.S. trucking terminals and in city truck drivers (with 6 repeat site visits), observing average shift concentrations in truck cabs and at multiple background and work area locations within each terminal. In this paper, we characterize occupational exposure to 18 different VOCs and aldehydes, as well as relationships with particulate mass (elemental carbon in PM < 1 μ m and PM2.5) across locations to determine source characteristics. Our results show that occupational exposure to VOCs and aldehydes varies significantly across the different sampling locations within each terminal, with significantly higher exposures noted in the work environments over background levels (p < 0.01). A structural equation model performed well in predicting terminal exposures to VOCs and aldehydes as a function of job, background levels, weather conditions, proximity to a major road, and geographic location (R2 = 0.2–0.4 work area; R2 = 0.5–0.9 background). PMID:17993162

  9. Synthesis of Discodermolide Subunits by S(E)2' Addition of Nonracemic Allenylstannanes to Aldehydes.

    PubMed

    Marshall, James A.; Lu, Zhi-Hui; Johns, Brian A.

    1998-02-01

    Three subunits, 15, 29, and 34, of the immunosuppressant discodermolide were prepared starting from (S)-3-[(tert-butyldimethylsilyl)oxy]-2-methylpropanal ((S)-1) and the enantioenriched allenylstannanes (P)-2a, (P)-2b, and (P)-31. The route to 15 involved BF(3)-promoted addition of stannane (P)-2a to aldehyde (S)-1 which afforded the syn,syn-homopropargylic alcohol adduct 3 in 97% yield. The derived p-methoxybenzylidene acetal 5 was treated with Red-Al to effect cleavage of the pivalate and reduction of the double bond leading to the (E)-allylic alcohol 6. Sharpless epoxidation and subsequent addition of Me(2)CuCNLi(2) yielded the syn,syn,syn,anti stereopentad, diol 8. Protection of the secondary alcohol and oxidation of the primary gave aldehyde 12, which was treated with the alpha-bromo allylsilane 13 and CrCl(2), followed by NaH to effect elimination to the diene 15. A similar sequence was employed to prepare aldehyde 29. In this case aldehyde (S)-1 was converted to the anti,syn-homopropargylic alcohol 20 by treatment with the allenyl indium reagent formed in situ from allenylstannane (P)-2b and InBr(3). Epoxy alcohol 24, prepared from alcohol 20 by the above-described sequence, was reduced with Red-Al to afford diol 25. Protection of the secondary alcohol and oxidation of the primary completed the synthesis of 29. The anti,syn-homopropargylic alcohol 32 was obtained through addition of the allenic indium reagent, from allenylstannane (P)-31, to aldehyde (S)-1. Protection of the derived diol 33 as the p-methoxybenzylidene acetal afforded the third subunit, acetylene 34. Addition of the lithio derivative of 34 to aldehyde 29 gave alcohol 35 with the carbinyl stereochemistry needed for C7 of discodermolide as the major product.

  10. Chemistry and Biology of DNA Containing 1,N2-Deoxyguanosine Adducts of the α,β-Unsaturated Aldehydes Acrolein, Crotonaldehyde, and 4-Hydroxynonenal

    PubMed Central

    2009-01-01

    The α,β-unsaturated aldehydes (enals) acrolein, crotonaldehyde, and trans-4-hydroxynonenal (4-HNE) are products of endogenous lipid peroxidation, arising as a consequence of oxidative stress. The addition of enals to dG involves Michael addition of the N2-amine to give N2-(3-oxopropyl)-dG adducts, followed by reversible cyclization of N1 with the aldehyde, yielding 1,N2-dG exocyclic products. The 1,N2-dG exocyclic adducts from acrolein, crotonaldehyde, and 4-HNE exist in human and rodent DNA. The enal-induced 1,N2-dG lesions are repaired by the nucleotide excision repair pathway in both Escherichia coli and mammalian cells. Oligodeoxynucleotides containing structurally defined 1,N2-dG adducts of acrolein, crotonaldehyde, and 4-HNE were synthesized via a postsynthetic modification strategy. Site-specific mutagenesis of enal adducts has been carried out in E. coli and various mammalian cells. In all cases, the predominant mutations observed are G→T transversions, but these adducts are not strongly miscoding. When placed into duplex DNA opposite dC, the 1,N2-dG exocyclic lesions undergo ring opening to the corresponding N2-(3-oxopropyl)-dG derivatives. Significantly, this places a reactive aldehyde in the minor groove of DNA, and the adducted base possesses a modestly perturbed Watson−Crick face. Replication bypass studies in vitro indicate that DNA synthesis past the ring-opened lesions can be catalyzed by pol η, pol ι, and pol κ. It also can be accomplished by a combination of Rev1 and pol ζ acting sequentially. However, efficient nucleotide insertion opposite the 1,N2-dG ring-closed adducts can be carried out only by pol ι and Rev1, two DNA polymerases that do not rely on the Watson−Crick pairing to recognize the template base. The N2-(3-oxopropyl)-dG adducts can undergo further chemistry, forming interstrand DNA cross-links in the 5′-CpG-3′ sequence, intrastrand DNA cross-links, or DNA−protein conjugates. NMR and mass spectrometric analyses

  11. Identification of the Helicobacter pylori VacA Toxin Domain Active in the Cell Cytosol

    PubMed Central

    de Bernard, Marina; Burroni, Daniela; Papini, Emanuele; Rappuoli, Rino; Telford, John; Montecucco, Cesare

    1998-01-01

    Cells exposed to Helicobacter pylori toxin VacA develop large vacuoles which originate from massive swelling of membranous compartments at late stages of the endocytic pathway. When expressed in the cytosol, VacA induces vacuolization as it does when added from outside. This and other evidence indicate that VacA is a toxin capable of entering the cell cytosol, where it displays its activity. In this study, we have used cytosolic expression to identify the portion of the toxin molecule responsible for the vacuolating activity. VacA mutants with deletions at the C and N termini were generated, and their activity was analyzed upon expression in HeLa cells. We found that the vacuolating activity of VacA resides in the amino-terminal region, the whole of which is required for its intracellular activity. PMID:9826387

  12. Modulation of the cytosolic androgen receptor in striated muscle by sex steroids

    NASA Technical Reports Server (NTRS)

    Rance, N. E.; Max, S. E.

    1982-01-01

    The influence of orchiectomy (GDX) and steroid administration on the level of the cytosolic androgen receptor in the rat levator ani muscle and in rat skeletal muscles (tibialis anterior and extensor digitorum longus) was studied. Androgen receptor binding to muscle cytosol was measured using H-3 methyltrienolone (R1881) as ligand, 100 fold molar excess unlabeled R1881 to assess nonspecific binding, and 500 fold molar excess of triamcinolone acetonide to prevent binding to glucocorticoid and progestin receptors. Results demonstrate that modification of the levels of sex steroids can alter the content of androgen receptors of rat striated muscle. Data suggest that: (1) cytosolic androgen receptor levels increase after orchiectomy in both levator ani muscle and skeletal muscle; (2) the acute increase in receptor levels is blocked by an inhibitor of protein synthesis; and (3) administration of estradiol-17 beta to castrated animals increases receptor binding in levator ani muscle but not in skeletal muscle.

  13. Listeria monocytogenes that lyse in the macrophage cytosol trigger AIM2-mediated pyroptosis

    PubMed Central

    Sauer, John-Demian; Witte, Chelsea E.; Zemansky, Jason; Hanson, Bill; Lauer, Peter; Portnoy, Daniel A.

    2010-01-01

    Summary To gain insight into the mechanisms by which host cells detect cytosolic invasion by intracellular pathogens, a genetic screen was performed to identify Listeria monocytogenes mutants that induced altered levels of host cell death. A mutation in lmo2473 resulted in hyper-stimulation of host cell death and IL-1β secretion (pyroptosis) following bacteriolysis in the macrophage cytosol. In addition, strains engineered to lyse in the cytosol by expression of both bacteriophage holin and lysin or induced to lyse by treatment with ampicillin stimulated pyroptosis. Pyroptosis was independent of the Nlrp3 and Nlrc4 receptors, but dependent on ASC and AIM2. Importantly, wild type L. monocytogenes were also found to lyse, albeit at low levels, and trigger AIM2-dependent pyroptosis. Since AIM2 is activated by DNA, these data suggested that pyroptosis is triggered by bacterial DNA released during lysis. PMID:20417169

  14. Bcl-xL retrotranslocates Bax from the mitochondria into the cytosol

    PubMed Central

    Edlich, Frank; Banerjee, Soojay; Suzuki, Motoshi; Cleland, Megan M.; Arnoult, Damien; Wang, Chunxin; Neutzner, Albert; Tjandra, Nico; Youle, Richard J.

    2011-01-01

    Summary The Bcl-2 family member Bax translocates from the cytosol to mitochondria where it oligomerizes and permeabilizes the mitochondrial outer membrane to promote apoptosis. Bax activity is counteracted by pro-survival Bcl-2 proteins, but how they inhibit Bax remains controversial, because they neither co-localize nor form stable complexes with Bax. We constrained Bax in its native cytosolic conformation within cells using intramolecular disulfide tethers. Bax tethers disrupt interaction with Bcl-xL in detergents and cell free MOMP activity, but unexpectedly induce Bax accumulation on mitochondria. Fluorescence Loss in Photobleaching (FLIP) reveals constant retrotranslocation of wt Bax, but not tethered Bax, from the mitochondria into the cytoplasm of healthy cells. Bax retrotranslocation depends on pro-survival Bcl-2 family proteins and inhibition of retrotranslocation correlates with Bax accumulation on the mitochondria. We propose that Bcl-xL inhibits and maintains Bax in the cytosol by constant retrotranslocation of mitochondrial Bax. PMID:21458670

  15. L-Cysteine Desulfhydrase 1 modulates the generation of the signaling molecule sulfide in plant cytosol

    PubMed Central

    Romero, Luis C.; García, Irene; Gotor, Cecilia

    2013-01-01

    Consistent with data in animal systems, experimental evidence highlights sulfide as a signaling molecule of equal importance to NO and H2O2 in plant systems. In mammals, two cytosolic enzymes, cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE), have been shown to be responsible for the endogenous production of sulfide. L-cysteine desulfhydrase 1 (DES1) has been recently established as the only enzyme that is involved in the generation of hydrogen sulfide in plant cytosol. Although plants have an available source of sulfide within chloroplasts, the basic stromal pH prevents sulfide release into the cytosol. Therefore, DES1 is essential for the production of sulfide for signaling purposes. PMID:23428891

  16. Cytosol-dependent membrane fusion in ER, nuclear envelope and nuclear pore assembly: biological implications.

    PubMed

    Rafikova, Elvira R; Melikov, Kamran; Chernomordik, Leonid V

    2010-01-01

    Endoplasmic reticulum and nuclear envelope rearrangements after mitosis are often studied in the reconstitution system based on Xenopus egg extract. In our recent work we partially replaced the membrane vesicles in the reconstitution mix with protein-free liposomes to explore the relative contributions of cytosolic and transmembrane proteins. Here we discuss our finding that cytosolic proteins mediate fusion between membranes lacking functional transmembrane proteins and the role of membrane fusion in endoplasmic reticulum and nuclear envelope reorganization. Cytosol-dependent liposome fusion has allowed us to restore, without adding transmembrane nucleoporins, functionality of nuclear pores, their spatial distribution and chromatin decondensation in nuclei formed at insufficient amounts of membrane material and characterized by only partial decondensation of chromatin and lack of nuclear transport. Both the mechanisms and the biological implications of the discovered coupling between spatial distribution of nuclear pores, chromatin decondensation and nuclear transport are discussed.

  17. Phononic Phase Conjugation in an Optomechanical System

    NASA Astrophysics Data System (ADS)

    Buchmann, Lukas; Wright, Ewan; Meystre, Pierre

    2013-05-01

    We study theoretically the phase conjugation of a phononic field in an optomechanical system with two mechanical modes coupled to a common optical field. Phase conjugation becomes the dominant process for an appropriate choice of driving field parameters, and he effective coupling coefficients between phonon modes can result in amplification and entanglement, phase-conjugation or a mixture thereof. We discuss surprising consequences of mechanical phase-conjugation that could lead to the preparation of mechanical states with negative temperature, the improvement of quantum memories and the study of the quantum-classical transition. Supported by DARPA ORCHID program.

  18. Identification of Ubiquitin-specific Protease 9X (USP9X) as a Deubiquitinase Acting on Ubiquitin-Peroxin 5 (PEX5) Thioester Conjugate*

    PubMed Central

    Grou, Cláudia P.; Francisco, Tânia; Rodrigues, Tony A.; Freitas, Marta O.; Pinto, Manuel P.; Carvalho, Andreia F.; Domingues, Pedro; Wood, Stephen A.; Rodríguez-Borges, José E.; Sá-Miranda, Clara; Fransen, Marc; Azevedo, Jorge E.

    2012-01-01

    Peroxin 5 (PEX5), the peroxisomal protein shuttling receptor, binds newly synthesized peroxisomal matrix proteins in the cytosol and promotes their translocation across the organelle membrane. During the translocation step, PEX5 itself becomes inserted into the peroxisomal docking/translocation machinery. PEX5 is then monoubiquitinated at a conserved cysteine residue and extracted back into the cytosol in an ATP-dependent manner. We have previously shown that the ubiquitin-PEX5 thioester conjugate (Ub-PEX5) released into the cytosol can be efficiently disrupted by physiological concentrations of glutathione, raising the possibility that a fraction of Ub-PEX5 is nonenzymatically deubiquitinated in vivo. However, data suggesting that Ub-PEX5 is also a target of a deubiquitinase were also obtained in that work. Here, we used an unbiased biochemical approach to identify this enzyme. Our results suggest that ubiquitin-specific protease 9X (USP9X) is by far the most active deubiquitinase acting on Ub-PEX5, both in female rat liver and HeLa cells. We also show that USP9X is an elongated monomeric protein with the capacity to hydrolyze thioester, isopeptide, and peptide bonds. The strategy described here will be useful in identifying deubiquitinases acting on other ubiquitin conjugates. PMID:22371489

  19. Yttrium (amidate) complexes for catalytic C-N bond formation. Rapid, room temperature amidation of aldehydes.

    PubMed

    Thomson, Jaclyn A; Schafer, Laurel L

    2012-07-14

    Yttrium (amidate) precatalysts are highly active for the mild amidation of aldehydes with amines. Reactions occur at room temperature within 5 min in up to 98% isolated yield. These rare-earth systems are effective for this transformation in the absence of supplementary heat, light, base, or oxidants. The reaction proceeds with functionalized amines and/or aldehydes. A comparison of various amidate precatalysts in combination with reaction monitoring suggests that the targeted amide products formed during the reaction promote the formation of alternative catalytically active amidate species in situ.

  20. Application of a Sequential Reaction Model to PANS and Aldehyde Measurements in Two Urban Areas

    SciTech Connect

    Roberts, James M.; Stroud, C.; Jobson, B Tom T.; Trainer, Michael; Hereid, D.; Williams, E. J.; Fehsenfeld, Fred C.; Brune, W. H.; Martinez, M.; Harder, H.

    2001-12-15

    Measurements of peroxycarboxylic nitric anhydrides (= PAN, PPN, MPAN) and aldehydes (acetaldehyde, propanal, and methacrolein) were made at Nashville, Tennessee, in 1999 and Houston, Texas, in 2000. The data were interpreted with a sequential reaction model that included reaction of aldehydes with hydroxl radical and formation or loss of PANs mediated by peroxyacyl radicals. The comparison of the measured ratios with those predicted by the model showed disagreement for PAN/acetaldehyde and PPN/propanal in Nashville but agreement in Houston. These features are consistent with the relative importance of isoprene to PAN formation at each site.

  1. Inhibitory effects of terpene alcohols and aldehydes on growth of green alga Chlorella pyrenoidosa

    SciTech Connect

    Ikawa, Miyoshi; Mosley, S.P.; Barbero, L.J. )

    1992-10-01

    The growth of the green alga Chlorella pyrenoidosa was inhibited by terpene alcohols and the terpene aldehyde citral. The strongest activity was shown by citral. Nerol, geraniol, and citronellol also showed pronounced activity. Strong inhibition was linked to acyclic terpenes containing a primary alcohol or aldehyde function. Inhibition appeared to be taking place through the vapor phase rather than by diffusion through the agar medium from the terpene-treated paper disks used in the system. Inhibition through agar diffusion was shown by certain aged samples of terpene hydrocarbons but not by recently purchased samples.

  2. Effects of the biodiesel blend fuel on aldehyde emissions from diesel engine exhaust

    NASA Astrophysics Data System (ADS)

    Peng, Chiung-Yu; Yang, Hsi-Hsien; Lan, Cheng-Hang; Chien, Shu-Mei

    Interest in use of biodiesel fuels derived from vegetable oils or animal fats as alternative fuels for petroleum-based diesels has increased due to biodiesels having similar properties of those of diesels, and characteristics of renewability, biodegradability and potential beneficial effects on exhaust emissions. Generally, exhaust emissions of regulated pollutants are widely studied and the results favor biodiesels on CO, HC and particulate emissions; however, limited and inconsistent data are showed for unregulated pollutants, such as carbonyl compounds, which are also important indicators for evaluating available vehicle fuels. For better understanding biodiesel, this study examines the effects of the biodiesel blend fuel on aldehyde chemical emissions from diesel engine exhausts in comparison with those from the diesel fuel. Test engines (Mitsubishi 4M40-2AT1) with four cylinders, a total displacement of 2.84 L, maximum horsepower of 80.9 kW at 3700 rpm, and maximum torque of 217.6 N m at 2000 rpm, were mounted and operated on a Schenck DyNAS 335 dynamometer. Exhaust emission tests were performed several times for each fuel under the US transient cycle protocol from mileages of 0-80,000 km with an interval of 20,000 km, and two additional measurements were carried out at 40,000 and 80,000 km after maintenance, respectively. Aldehyde samples were collected from diluted exhaust by using a constant volume sampling system. Samples were extracted and analyzed by the HPLC/UV system. Dominant aldehydes of both fuels' exhausts are formaldehyde and acetaldehyde. These compounds together account for over 75% of total aldehyde emissions. Total aldehyde emissions for B20 (20% waste cooking oil biodiesel and 80% diesel) and diesel fuels are in the ranges of 15.4-26.9 mg bhp-h -1 and 21.3-28.6 mg bhp-h -1, respectively. The effects of increasing mileages and maintenance practice on aldehyde emissions are insignificant for both fuels. B20 generates slightly less emission than

  3. Derivatization of vinyl aldehydes with anthrone prior to high-performance liquid chromatography with fluorometric detection

    SciTech Connect

    Miller, B.E.; Danielson, N.D.

    1988-04-01

    Precolumn high-performance liquid chromatography derivatization of several vinyl aldehydes, specifically acrolein, crotonaldehyde, and methacrolein, has been studied by use of the reagent anthrone. After selective condensation of these ..cap alpha..- or ..beta..-unsaturated aldehydes to form fluorescent benzanthrone derivatives, separation of these compounds was facile on a 10-cm C-18 column. Although ultraviolet detection was possible, fluorescent detection proved more versatile and sensitive. Four liquor samples were subsequently assayed for acrolein and crotonaldehyde. Linearity for these compounds in alcoholic solutions ranged from 0.02 to at least 14 ppm with detection limits reaching down to 0.005 ppm.

  4. Retention of fluorescent probes during aldehyde-free anhydrous freeze-substitution.

    PubMed

    Hyde, G J; Davies, D S; Cole, L; Ashford, A E

    2003-05-01

    Fluorescent probes are widely used for microscopy of live-cell processes, but few such probes can also be used with classically fixed or otherwise immobilized material, and none has been used without aldehyde fixation, which can introduce artefacts of structure and probe localization. Here we show that the fluorescence patterns in fungal hyphae loaded with chloromethyl aminocoumarin (CMAC), and then anhydrously freeze-substituted, without any aldehyde fixation, are similar to those seen in living hyphae. Probe loss into the mounting medium (Spurr's resin) with CMAC and five other probes tested indicated that some unwanted solubilization of probe occurred during embedding, but nevertheless vacuoles could be imaged by their retention of probe.

  5. Enantioselective Multicomponent Condensation Reactions of Phenols, Aldehydes, and Boronates Catalyzed by Chiral Biphenols.

    PubMed

    Barbato, Keith S; Luan, Yi; Ramella, Daniele; Panek, James S; Schaus, Scott E

    2015-12-01

    Chiral diols and biphenols catalyze the multicomponent condensation reaction of phenols, aldehydes, and alkenyl or aryl boronates. The condensation products are formed in good yields and enantioselectivities. The reaction proceeds via an initial Friedel-Crafts alkylation of the aldehyde and phenol to yield an ortho-quinone methide that undergoes an enantioselective boronate addition. A cyclization pathway was discovered while exploring the scope of the reaction that provides access to chiral 2,4-diaryl chroman products, the core of which is a structural motif found in natural products. PMID:26576776

  6. Glutaredoxin GRXS17 Associates with the Cytosolic Iron-Sulfur Cluster Assembly Pathway1[OPEN

    PubMed Central

    Durand, Astrid Nagels; Ritter, Andrés; Klassen, Roland; Tohge, Takayuki; Fernie, Alisdair R.; Leidel, Sebastian A.; Pauwels, Laurens

    2016-01-01

    Cytosolic monothiol glutaredoxins (GRXs) are required in iron-sulfur (Fe-S) cluster delivery and iron sensing in yeast and mammals. In plants, it is unclear whether they have similar functions. Arabidopsis (Arabidopsis thaliana) has a sole class II cytosolic monothiol GRX encoded by GRXS17. Here, we used tandem affinity purification to establish that Arabidopsis GRXS17 associates with most known cytosolic Fe-S assembly (CIA) components. Similar to mutant plants with defective CIA components, grxs17 loss-of-function mutants showed some degree of hypersensitivity to DNA damage and elevated expression of DNA damage marker genes. We also found that several putative Fe-S client proteins directly bind to GRXS17, such as XANTHINE DEHYDROGENASE1 (XDH1), involved in the purine salvage pathway, and CYTOSOLIC THIOURIDYLASE SUBUNIT1 and CYTOSOLIC THIOURIDYLASE SUBUNIT2, both essential for the 2-thiolation step of 5-methoxycarbonylmethyl-2-thiouridine (mcm5s2U) modification of tRNAs. Correspondingly, profiling of the grxs17-1 mutant pointed to a perturbed flux through the purine degradation pathway and revealed that it phenocopied mutants in the elongator subunit ELO3, essential for the mcm5 tRNA modification step, although we did not find XDH1 activity or tRNA thiolation to be markedly reduced in the grxs17-1 mutant. Taken together, our data suggest that plant cytosolic monothiol GRXs associate with the CIA complex, as in other eukaryotes, and contribute to, but are not essential for, the correct functioning of client Fe-S proteins in unchallenged conditions. PMID:27503603

  7. Distinction between Cytosol and Chloroplast Fructose-Bisphosphate Aldolases from Pea, Wheat, and Corn Leaves

    PubMed Central

    Schnarrenberger, Claus; Krüger, Ingo

    1986-01-01

    A reinvestigation of cytosol and chloroplast fructose-1,6-bisphosphate (FBP) aldolases from pea (Pisum sativum L.), wheat (Triticum aestivum L.) and corn leaves (Zea mays L.) revealed that the two isoenzymes can be separated by chromatography on diethylaminoethyl (DEAE)-cellulose although the separation was often less clear-cut than for the two aldolases from spinach leaves. Definite distinction was achieved by immunoprecipitation of the two isoenzymes with antisera raised against the respective isoenzymes from spinach leaves. The proportion of cytosol aldolase as part of total aldolase activity was 8, 9, 14, and 4.5% in spinach (Spinacia oleracea L.), pea, wheat, and corn leaves, respectively. For corn leaves we also obtained values of up to 15%. The Km (FBP) values were about 5-fold lower for the cytosol (1.1-2.3 micromolar concentration) than for the chloroplast enzymes (8.0-10.5 micromolar concentration). The respective Km (fructose-1-phosphate, F1P) values were about equal for the cytosol (1.0-2.3 millimolar concentration) and for the chloroplast aldolase (0.6-1.7 millimolar concentration). The ratio V (FIP)/V (FBP) was 0.20 to 0.27 for the cytosol and 0.07 to 0.145 for the chloroplast aldolase. Thus, cytosol and chloroplast aldolases from spinach, pea, wheat, and corn leaves differ quite considerably in the elution pattern from DEAE-cellulose, in immunoprecipitability with antisera against the respective isoenzymes from spinach leaves, and in the affinity to FBP. PMID:16664617

  8. Human Nbp35 is essential for both cytosolic iron-sulfur protein assembly and iron homeostasis.

    PubMed

    Stehling, Oliver; Netz, Daili J A; Niggemeyer, Brigitte; Rösser, Ralf; Eisenstein, Richard S; Puccio, Helene; Pierik, Antonio J; Lill, Roland

    2008-09-01

    The maturation of cytosolic iron-sulfur (Fe/S) proteins in mammalian cells requires components of the mitochondrial iron-sulfur cluster assembly and export machineries. Little is known about the cytosolic components that may facilitate the assembly process. Here, we identified the cytosolic soluble P-loop NTPase termed huNbp35 (also known as Nubp1) as an Fe/S protein, and we defined its role in the maturation of Fe/S proteins in HeLa cells. Depletion of huNbp35 by RNA interference decreased cell growth considerably, indicating its essential function. The deficiency in huNbp35 was associated with an impaired maturation of the cytosolic Fe/S proteins glutamine phosphoribosylpyrophosphate amidotransferase and iron regulatory protein 1 (IRP1), while mitochondrial Fe/S proteins remained intact. Consequently, huNbp35 is specifically involved in the formation of extramitochondrial Fe/S proteins. The impaired maturation of IRP1 upon huNbp35 depletion had profound consequences for cellular iron metabolism, leading to decreased cellular H-ferritin, increased transferrin receptor levels, and higher transferrin uptake. These properties clearly distinguished huNbp35 from its yeast counterpart Nbp35, which is essential for cytosolic-nuclear Fe/S protein assembly but plays no role in iron regulation. huNbp35 formed a complex with its close homologue huCfd1 (also known as Nubp2) in vivo, suggesting the existence of a heteromeric P-loop NTPase complex that is required for both cytosolic Fe/S protein assembly and cellular iron homeostasis.

  9. Human Nbp35 Is Essential for both Cytosolic Iron-Sulfur Protein Assembly and Iron Homeostasis▿

    PubMed Central

    Stehling, Oliver; Netz, Daili J. A.; Niggemeyer, Brigitte; Rösser, Ralf; Eisenstein, Richard S.; Puccio, Helene; Pierik, Antonio J.; Lill, Roland

    2008-01-01

    The maturation of cytosolic iron-sulfur (Fe/S) proteins in mammalian cells requires components of the mitochondrial iron-sulfur cluster assembly and export machineries. Little is known about the cytosolic components that may facilitate the assembly process. Here, we identified the cytosolic soluble P-loop NTPase termed huNbp35 (also known as Nubp1) as an Fe/S protein, and we defined its role in the maturation of Fe/S proteins in HeLa cells. Depletion of huNbp35 by RNA interference decreased cell growth considerably, indicating its essential function. The deficiency in huNbp35 was associated with an impaired maturation of the cytosolic Fe/S proteins glutamine phosphoribosylpyrophosphate amidotransferase and iron regulatory protein 1 (IRP1), while mitochondrial Fe/S proteins remained intact. Consequently, huNbp35 is specifically involved in the formation of extramitochondrial Fe/S proteins. The impaired maturation of IRP1 upon huNbp35 depletion had profound consequences for cellular iron metabolism, leading to decreased cellular H-ferritin, increased transferrin receptor levels, and higher transferrin uptake. These properties clearly distinguished huNbp35 from its yeast counterpart Nbp35, which is essential for cytosolic-nuclear Fe/S protein assembly but plays no role in iron regulation. huNbp35 formed a complex with its close homologue huCfd1 (also known as Nubp2) in vivo, suggesting the existence of a heteromeric P-loop NTPase complex that is required for both cytosolic Fe/S protein assembly and cellular iron homeostasis. PMID:18573874

  10. Identification and characterization of alkenyl hydrolase (lysoplasmalogenase) in microsomes and identification of a plasmalogen-active phospholipase A2 in cytosol of small intestinal epithelium.

    PubMed

    Jurkowitz, M S; Horrocks, L A; Litsky, M L

    1999-02-25

    A lysoplasmalogenase (EC 3.3.2.2; EC 3.3.2.5) that liberates free aldehyde from 1-alk-1'-enyl-sn-glycero-3-phospho-ethanolamine or -choline (lysoplasmalogen) was identified and characterized in rat gastrointestinal tract epithelial cells. Glycerophosphoethanolamine was produced in the reaction in equimolar amounts with the free aldehyde. The microsomal membrane associated enzyme was present throughout the length of the small intestines, with the highest activity in the jejunum and proximal ileum. The rate of alkenyl ether bond hydrolysis was dependent on the concentrations of microsomal protein and substrate, and was linear with respect to time. The enzyme hydrolyzed both ethanolamine- and choline-lysoplasmalogens with similar affinities; the Km values were 40 and 66 microM, respectively. The enzyme had no activity with 1-alk-1'-enyl-2-acyl-sn-glycero-3-phospho-ethanolamine or -choline (intact plasmalogen), thus indicating enzyme specificity for a free hydroxyl group at the sn-2 position. The specific activities were 70 nmol/min/mg protein and 57 nmol/min/mg protein, respectively, for ethanolamine- and choline-lysoplasmalogen. The pH optimum was between 6.8 and 7.4. The enzyme required no known cofactors and was not affected by low mM levels of Ca2+, Mg2+, EDTA, or EGTA. The detergents, Triton X-100, deoxycholate, and octyl glucoside inhibited the enzyme. The chemical and physical properties of the lysoplasmalogenase were very similar to those of the enzyme in liver and brain microsomes. In developmental studies the specific activities of the small intestinal and liver enzymes increased markedly, 11.1- and 3.4-fold, respectively, in the first approximately 40 days of postnatal life. A plasmalogen-active phospholipase A2 activity was identified in the cytosol of the small intestines (3.3 nmol/min/mg protein) and liver (0.3 nmol/min/mg protein) using a novel coupled enzyme assay with microsomal lysoplasmalogenase as the coupling enzyme.

  11. Preparation and characterization of a nontoxic polysaccharide-protein conjugate that induces active immunity and passively protective antibody against Pseudomonas aeruginosa immunotype 1 in mice.

    PubMed Central

    Tsay, G C; Collins, M S

    1984-01-01

    Acid treatment of Pseudomonas aeruginosa immunotype 1 lipopolysaccharide generated a low-molecular-weight polysaccharide fraction that was detectable in agar gel immunodiffusion but did not induce antibodies or resistance to infection in mice. The polysaccharide was treated with periodate to generate additional aldehyde groups. Oxidized polysaccharide was covalently coupled by reductive amination to 1,4-diaminobutyl-derivatized bovine serum albumin. Physical properties of the conjugate were characterized by gel filtration and high-pressure liquid chromatography. The gelation activity of the conjugate in the Limulus amoebocyte lysate assay was 4,000-fold less than native lipopolysaccharide by weight. Mice immunized with the conjugate resisted challenge with P. aeruginosa immunotype 1 that killed 90% of mice immunized with saline. Immunization with the conjugate vaccine induced humoral immunoglobulin G that passively protected normal and burned mice. These results indicate that conjugation of nonimmunogenic polysaccharide antigen of P. aeruginosa restores immunogenicity similar to that of native lipopolysaccharide without restoring endotoxicity inherent in lipopolysaccharide. PMID:6429046

  12. Fluorescence lifetime analysis and effect of magnesium ions on binding of NADH to human aldehyde dehydrogenase 1

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aldehyde dehydrogenase 1 (ALDH1) catalyzes oxidation of toxic aldehydes to carboxylic acids. Physiologic levels of Mg2+ ions influence ALDH1 activity in part by increasing NADH binding affinity to the enzyme thus reducing activity. By using time-resolved fluorescence spectroscopy, we have resolved t...

  13. Kinetic mechanism of an aldehyde reductase of Saccharomyces cerevisiae that relieves toxicity of furfural and 5-hydroxymethylfurfural

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An effective means of relieving the toxicity of furan aldehydes, furfural (FFA) and 5-hydroxymethylfurfural (HMF), on fermenting organisms is essential for achieving efficient fermentation of lignocellulosic biomass to ethanol and other products. Ari1p, an aldehyde reductase from Saccharomyces cerev...

  14. In vitro effects of aldehydes present in tobacco smoke on gene expression in human lung alveolar epithelial cells.

    PubMed

    Cheah, Nuan P; Pennings, Jeroen L A; Vermeulen, Jolanda P; van Schooten, Frederik J; Opperhuizen, Antoon

    2013-04-01

    Tobacco smoke consists of thousands of harmful components. A major class of chemicals found in tobacco smoke is formed by aldehydes, in particular formaldehyde, acetaldehyde and acrolein. The present study investigates the gene expression changes in human lung alveolar epithelial cells upon exposure to formaldehyde, acrolein and acetaldehyde at sub-cytotoxic levels. We exposed A549 cells in vitro to aldehydes and non-aldehyde chemicals (nicotine, hydroquinone and 2,5-dimethylfuran) present in tobacco smoke and used microarrays to obtain a global view of the transcriptomic responses. We compared responses of the individual aldehydes with that of the non-aldehydes. We also studied the response of the aldehydes when present in a mixture at relative concentrations as present in cigarette smoke. Formaldehyde gave the strongest response; a total of 66 genes were more than 1.5-fold differentially expressed mostly involved in apoptosis and DNA damage related processes, followed by acetaldehyde (57 genes), hydroquinone (55 genes) and nicotine (8 genes). For acrolein and the mixture only one gene was upregulated involved in oxidative stress. No gene expression effect was found for exposure to 2,5-dimethylfuran. Overall, aldehyde responses are primarily indicative for genotoxicity and oxidative stress. These two toxicity mechanisms are linked to respiratory diseases such as cancer and COPD, respectively. The present findings could be important in providing further understanding of the role of aldehydes emitted from cigarette smoke in the onset of pulmonary diseases.

  15. Kinetics of forming aldehydes in frying oils and their distribution in French fries revealed by LC-MS-based chemometrics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aldehydes are major secondary lipid oxidation products (LOPs) from heating vegetable oils and deep frying. The routes and reactions that generate aldehydes have been extensively investigated, but the sequences and kinetics of their formation in oils are poorly defined. In this study, a platform comb...

  16. In vitro effects of aldehydes present in tobacco smoke on gene expression in human lung alveolar epithelial cells.

    PubMed

    Cheah, Nuan P; Pennings, Jeroen L A; Vermeulen, Jolanda P; van Schooten, Frederik J; Opperhuizen, Antoon

    2013-04-01

    Tobacco smoke consists of thousands of harmful components. A major class of chemicals found in tobacco smoke is formed by aldehydes, in particular formaldehyde, acetaldehyde and acrolein. The present study investigates the gene expression changes in human lung alveolar epithelial cells upon exposure to formaldehyde, acrolein and acetaldehyde at sub-cytotoxic levels. We exposed A549 cells in vitro to aldehydes and non-aldehyde chemicals (nicotine, hydroquinone and 2,5-dimethylfuran) present in tobacco smoke and used microarrays to obtain a global view of the transcriptomic responses. We compared responses of the individual aldehydes with that of the non-aldehydes. We also studied the response of the aldehydes when present in a mixture at relative concentrations as present in cigarette smoke. Formaldehyde gave the strongest response; a total of 66 genes were more than 1.5-fold differentially expressed mostly involved in apoptosis and DNA damage related processes, followed by acetaldehyde (57 genes), hydroquinone (55 genes) and nicotine (8 genes). For acrolein and the mixture only one gene was upregulated involved in oxidative stress. No gene expression effect was found for exposure to 2,5-dimethylfuran. Overall, aldehyde responses are primarily indicative for genotoxicity and oxidative stress. These two toxicity mechanisms are linked to respiratory diseases such as cancer and COPD, respectively. The present findings could be important in providing further understanding of the role of aldehydes emitted from cigarette smoke in the onset of pulmonary diseases. PMID:23416264

  17. Quantification of aldehyde terminated heparin by SEC-MALLS-UV for the surface functionalization of polycaprolactone biomaterials.

    PubMed

    Irvine, Scott A; Steele, Terry W J; Bhuthalingam, Ramya; Li, Min; Boujday, Souhir; Prawirasatya, Melissa; Neoh, Koon Gee; Boey, Freddy Yin Chiang; Venkatraman, Subbu S

    2015-08-01

    A straight forward strategy of heparin surface grafting employs a terminal reactive-aldehyde group introduced through nitrous acid depolymerization. An advanced method that allows simultaneously monitoring of both heparin molar mass and monomer/aldehyde ratio by size exclusion chromatography, multi-angle laser light scattering and UV-absorbance (SEC-MALLS-UV) has been developed to improve upon heparin surface grafting. Advancements over older methods allow quantitative characterization by direct (aldehyde absorbance) and indirect (Schiff-based absorbance) evaluation of terminal functional aldehydes. The indirect quantitation of functional aldehydes through labeling with aniline (and the formation of a Schiff-base) allows independent quantitation of both polymer mass and terminal functional groups with the applicable UV mass extinction coefficients determined. The protocol was subsequently used to synthesize an optimized heparin-aldehyde that had minimal polydispersity (PDI<2) and high reaction yields (yield >60% by mass). The 8 kDa weight averaged molar mass heparin-aldehyde was then grafted on polycaprolactone (PCL), a common implant material. This optimized heparin-aldehyde retained its antithrombin activity, assessed in freshly drawn blood or surface immobilized on PCL films. Anticoagulant activity was equal to or better than the 24 kDa unmodified heparin it was fragmented from. PMID:26052108

  18. Quantification of aldehyde terminated heparin by SEC-MALLS-UV for the surface functionalization of polycaprolactone biomaterials.

    PubMed

    Irvine, Scott A; Steele, Terry W J; Bhuthalingam, Ramya; Li, Min; Boujday, Souhir; Prawirasatya, Melissa; Neoh, Koon Gee; Boey, Freddy Yin Chiang; Venkatraman, Subbu S

    2015-08-01

    A straight forward strategy of heparin surface grafting employs a terminal reactive-aldehyde group introduced through nitrous acid depolymerization. An advanced method that allows simultaneously monitoring of both heparin molar mass and monomer/aldehyde ratio by size exclusion chromatography, multi-angle laser light scattering and UV-absorbance (SEC-MALLS-UV) has been developed to improve upon heparin surface grafting. Advancements over older methods allow quantitative characterization by direct (aldehyde absorbance) and indirect (Schiff-based absorbance) evaluation of terminal functional aldehydes. The indirect quantitation of functional aldehydes through labeling with aniline (and the formation of a Schiff-base) allows independent quantitation of both polymer mass and terminal functional groups with the applicable UV mass extinction coefficients determined. The protocol was subsequently used to synthesize an optimized heparin-aldehyde that had minimal polydispersity (PDI<2) and high reaction yields (yield >60% by mass). The 8 kDa weight averaged molar mass heparin-aldehyde was then grafted on polycaprolactone (PCL), a common implant material. This optimized heparin-aldehyde retained its antithrombin activity, assessed in freshly drawn blood or surface immobilized on PCL films. Anticoagulant activity was equal to or better than the 24 kDa unmodified heparin it was fragmented from.

  19. Subgap Absorption in Conjugated Polymers

    DOE R&D Accomplishments Database

    Sinclair, M.; Seager, C. H.; McBranch, D.; Heeger, A. J; Baker, G. L.

    1991-01-01

    Along with X{sup (3)}, the magnitude of the optical absorption in the transparent window below the principal absorption edge is an important parameter which will ultimately determine the utility of conjugated polymers in active integrated optical devices. With an absorptance sensitivity of < 10{sup {minus}5}, Photothermal Deflection Spectroscopy (PDS) is ideal for determining the absorption coefficients of thin films of transparent'' materials. We have used PDS to measure the optical absorption spectra of the conjugated polymers poly(1,4-phenylene-vinylene) (and derivitives) and polydiacetylene-4BCMU in the spectral region from 0.55 eV to 3 eV. Our spectra show that the shape of the absorption edge varies considerably from polymer to polymer, with polydiacetylene-4BCMU having the steepest absorption edge. The minimum absorption coefficients measured varied somewhat with sample age and quality, but were typically in the range 1 cm{sup {minus}1} to 10 cm{sup {minus}1}. In the region below 1 eV, overtones of C-H stretching modes were observed, indicating that further improvements in transparency in this spectral region might be achieved via deuteration of fluorination.

  20. Progress in the preparation of peptide aldehydes via polymer supported IBX oxidation and scavenging by threonyl resin.

    PubMed

    Sorg, Gerhard; Thern, Bernd; Mader, Oliver; Rademann, Jörg; Jung, Günther

    2005-03-01

    Peptide aldehydes are of interest due to their inhibitory properties toward numerous classes of proteolytic enzymes such as caspases or the proteasome. A novel access to peptide aldehydes is described using a combination of solid phase peptide synthesis with polymer-assisted solution phase synthesis based on the oxidation of peptide alcohols with a mild and selective polymer-bound IBX derivative. The oxidation is followed by selective purification via scavenging the peptide aldehyde in a capture-release procedure using threonine attached to an aminomethyl resin. Peptide aldehydes are obtained in excellent purity and satisfying yield. The optical integrity of the C-terminal residue is conserved in a high degree. The procedures are compatible with the use of common side-chain protecting groups. The potential for using the method in parallel approaches is very advantageous. A small collection of new and known peptide aldehydes has been tested for inhibitory activity against caspases 1 and 3.

  1. Kinetic models of conjugated metabolic cycles

    NASA Astrophysics Data System (ADS)

    Ershov, Yu. A.

    2016-01-01

    A general method is developed for the quantitative kinetic analysis of conjugated metabolic cycles in the human organism. This method is used as a basis for constructing a kinetic graph and model of the conjugated citric acid and ureapoiesis cycles. The results from a kinetic analysis of the model for these cycles are given.

  2. Description of charge conjugation from first principles

    SciTech Connect

    Lujan-Peschard, C.; Napsuciale, M.

    2006-09-25

    We construct the charge conjugation operator as a unitary automorphism in the spinor space ((1/2), 0) + (0 (1/2)) from first principles. We calculate its eigenspinors and derive the equation of motion they satisfy. The mapping associated to charge conjugation is constructed from parity eigenstates which are considered as particle and antiparticle.

  3. The Conjugate Acid-Base Chart.

    ERIC Educational Resources Information Center

    Treptow, Richard S.

    1986-01-01

    Discusses the difficulties that beginning chemistry students have in understanding acid-base chemistry. Describes the use of conjugate acid-base charts in helping students visualize the conjugate relationship. Addresses chart construction, metal ions, buffers and pH titrations, and the organic functional groups and nonaqueous solvents. (TW)

  4. Intermediate role of α-keto acids in the formation of Strecker aldehydes.

    PubMed

    Hidalgo, Francisco J; Delgado, Rosa M; Zamora, Rosario

    2013-11-15

    The ability of α-keto acids to covert amino acids into Strecker aldehydes was investigated in an attempt to both identify new pathways for Strecker degradation, and analyse the role of α-keto acids as intermediate compounds in the formation of Strecker aldehydes by oxidised lipids. The results obtained indicated that phenylalanine was converted into phenylacetaldehyde to a significant extent by all α-keto acids assayed; glyoxylic acid being the most reactive α-keto acid for this reaction. It has been proposed that the reaction occurs by formation of an imine between the keto group of the α-keto acid, and the amino group of the amino acid. This then undergoes an electronic rearrangement with the loss of carbon dioxide to produce a new imine. This final imine is the origin of both the Strecker aldehyde and the amino acid from which the α-keto acid is derived. When glycine was incubated in the presence of 4,5-epoxy-2-decenal, the amino acid was converted into glyoxylic acid, and this α-keto acid was then able to convert phenylalanine into phenylacetaldehyde. All these results suggest that Strecker aldehydes can be produced by amino acid degradation initiated by different reactive carbonyl compounds, included those coming from amino acids and proteins. In addition, α-keto acids may act as intermediates for the Strecker degradation of amino acids by oxidised lipids.

  5. Actin Cys374 as a nucleophilic target of alpha,beta-unsaturated aldehydes.

    PubMed

    Dalle-Donne, Isabella; Carini, Marina; Vistoli, Giulio; Gamberoni, Luca; Giustarini, Daniela; Colombo, Roberto; Maffei Facino, Roberto; Rossi, Ranieri; Milzani, Aldo; Aldini, Giancarlo

    2007-03-01

    We have recently shown that actin can be modified by the Michael addition of 4-hydroxynonenal to Cys374. Here, we have exposed purified actin at increasing acrolein concentrations and have identified the sites of acrolein addition using LC-ESI-MS/MS. Acrolein reacted with Cys374, His87, His173, and, minimally, His40. Cys374 adduction by both 4-hydroxynonenal and acrolein negligibly affected the polymerization of aldehyde-modified (carbonylated) actin, as shown by fluorescence measurements. Differently, acrolein binding at histidine residues, when Cys374 was completely saturated, inhibited polymerization in a dose-dependent manner. Molecular modeling analyses indicated that structural distortions of the ATP-binding site, induced by four acrolein-Michael adducts, could explain the changes in the polymerization process. Aldehyde binding to Cys374 does not alter significantly actin polymerization because this residue is located in a very flexible region, whose covalent modifications do not alter the protein folding. These data demonstrate that Cys374 represents the primary target site of alpha,beta-unsaturated aldehyde addition to actin in vitro. As Cys374 is a preferential target for various oxidative/nitrosative modifications, and actin is one of the main carbonylated proteins in vivo, these findings also suggest that the highly reactive Cys374 could serve as a carbonyl scavenger of reactive alpha,beta-unsaturated aldehydes and other electrophilic lipids.

  6. Two-Carbon Homologation of Ketones to 3-Methyl Unsaturated Aldehydes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The usual scheme of two-carbon homologation of ketones to 3-methyl unsaturated aldehydes by Horner-Wadsworth-Emmons condensations with phosphonate esters, such as triethyl-2-phosphonoacetate, involves three steps. The phosphonate condensation step results in extension of the carbon chain by two carb...

  7. New HPLC methods to quantitate terpenoid aldehydes in foliage of cotton (Gossypium)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The cotton plant (Gossypium) produces protective terpenoid aldehydes in lysigenous pigment glands. These terpenoids include hemigossypolone, hemigossypolone-6-methyl ether, gossypol, gossypol-6-methyl ether, gossypol-6,6'-dimethyl ether, heliocides H1, H2, H3 and H4, and heliocides B1, B2, B3 and B4...

  8. Laboratory evaluation of an aldehyde scrubber system specifically for the detection of acrolein.

    PubMed

    Knighton, W Berk; Herndon, Scott C; Shorter, Joanne H; Miake-Lye, Richard C; Zahniser, Mark S; Akiyama, Kenichi; Shimono, Akio; Kitasaka, Kazuya; Shimajiri, Hatsumi; Sugihara, Koichi

    2007-11-01

    We demonstrate the use of an aldehyde scrubber system to resolve isobaric aldehyde/alkene interferences in a proton transfer reaction mass spectrometer (PTR-MS) by selectively removing the aldehydes from the gas mixture without loss of quantitative information for the alkene components. The aldehyde scrubber system uses a bisulfite solution, which scrubs carbonyl compounds from the gas stream by forming water-soluble carbonyl bisulfite addition products, and has been evaluated using a synthetic mixture of acrolein and isoprene. Trapping efficiencies of acrolein exceeded 97%, whereas the transmission efficiency of isoprene was better than 92%. Quantification of the PTR-MS response to acrolein was validated through an intercomparison study that included two derivatization methods, dinitrophenylhydrazine (DNPH) and O-(4-cyano-2-ethoxybenzyl)hydroxylamine (CNET), and a spectroscopic method using a quantum cascade laser infrared absorption spectroscopy (QCL) instrument. Finally, using cigarette smoke as a complex matrix, the acrolein content was assessed using the scrubber and compared with direct QCL-based detection. PMID:18069460

  9. Aldehyde dehydrogenase-2 regulates nociception in rodent models of acute inflammatory pain

    PubMed Central

    Zambelli, Vanessa O.; Gross, Eric R.; Chen, Che-Hong; Gutierrez, Vanessa P.; Cury, Yara; Mochly-Rosen, Daria

    2014-01-01

    Exogenous aldehydes can cause pain in animal models, suggesting that aldehyde dehydrogenase 2 (ALDH2), which metabolizes many aldehydes, may regulate nociception. To test this hypothesis, we generated a knock-in mouse with an inactivating point mutation in ALDH2 (ALDH2*2), which is also present in human ALDH2 of ~540 million East Asians. The ALDH2*1/*2 heterozygotic mice exhibited a larger response to painful stimuli than their wild-type littermates, and this heightened nociception was inhibited by an ALDH2-selective activator (Alda-1). No effect on inflammation per se was observed. Using a rat model, we then showed that nociception tightly correlated with ALDH activity (R2=0.90) and that reduced nociception was associated with less early growth response protein 1 (EGR1) in the spinal cord and less reactive aldehyde accumulation at the insult site (including acetaldehyde and 4-hydroxynonenal). Further, acetaldehyde and formalin-induced nociceptive behavior was greater in the ALDH2*1/*2 mice than wild-type mice. Finally, Alda-1 treatment was also beneficial when given even after the inflammatory agent was administered. Our data in rodent models suggest that the mitochondrial enzyme ALDH2 regulates nociception and could serve as a molecular target for pain control, with ALDH2 activators, such as Alda-1, as potential non-narcotic cardiac-safe analgesics. Furthermore, our results suggest a possible genetic basis for East Asians’ apparent lower pain tolerance. PMID:25163478

  10. Mitochondrial aldehyde dehydrogenase 2 protects gastric mucosa cells against DNA damage caused by oxidative stress.

    PubMed

    Duan, Yantao; Gao, Yaohui; Zhang, Jun; Chen, Yinan; Jiang, Yannan; Ji, Jun; Zhang, Jianian; Chen, Xuehua; Yang, Qiumeng; Su, Liping; Zhang, Jun; Liu, Bingya; Zhu, Zhenggang; Wang, Lishun; Yu, Yingyan

    2016-04-01

    Mitochondrial aldehyde dehydrogenase 2 (ALDH2) is a member of the aldehyde dehydrogenase superfamily and is involved with the metabolic processing of aldehydes. ALDH2 plays a cytoprotective role by removing aldehydes produced during normal metabolism. We examined the cytoprotective role of ALDH2 specifically in gastric mucosa cells. Overexpression of ALDH2 increased the viability of gastric mucosa cells treated with H2O2, while knockdown of ALDH2 had an opposite effect. Moreover, overexpression of ALDH2 protected gastric mucosa cells against oxidative stress-induced apoptosis as determined by flow cytometry, Hoechst 33342, and TUNEL assays. Consistently, ALDH2 knockdown had an opposite effect. Additionally, DNA damage was ameliorated in ALDH2-overexpressing gastric mucosa cells treated with H2O2. We further identified that this cytoprotective role of ALDH2 was mediated by metabolism of 4-hydroxynonenal (4-HNE). Consistently, 4-HNE mimicked the oxidative stress induced by H2O2 in gastric mucosa cells. Treatment with 4-HNE increased levels of DNA damage in ALDH2-knockdown GES-1 cells, while overexpression of ALDH2 decreased 4-HNE-induced DNA damage. These findings suggest that ALDH2 can protect gastric mucosa cells against DNA damage caused by oxidative stress by reducing levels of 4-HNE.

  11. A HIGHLY STEREOSELECTIVE, NOVEL COUPLING REACTION BETWEEN ALKYNES WITH ALDEHYDES. (R828129)

    EPA Science Inventory

    In the presence of indium triflate or gallium chloride, a novel coupling between internal alkynes and aldehydes occurred to give unsaturated ketones and [4+1] annulation products.


    Graphical Abstrac...

  12. Modification of growth of neuroblastoma cells in syngeneic mice by aldehyde-treated neuroblastoma cells.

    PubMed

    Bertolini, L; Diamond, L; Revoltella, R

    1976-06-01

    Pretreatment of syngeneic strain A mice with aldehyde-fixed neuroblastoma cells (clone NB6R) almost completely protected the mice against challenge with viable NB6R cells. In contrast, tumor growth was enhanced in mice treated with fixed cells after challenge with viable cells.

  13. Aroma chemicals: Reference sources for perfume and flavour ingredients with special reference to cinnamic aldehyde.

    PubMed

    Collins, F W; Mitchell, J C

    1975-01-01

    Bibliographic sources for the complex subject of aroma chemicals are reviewed. The references are not comprehensive but are those which we found to be of value in finding out some of the opportunities for contact with a sensitizing chemical compound, cinnamic aldehyde.

  14. Enzymatic conversion of atmospheric aldehydes into alcohol in a phospholipid polymer film.

    PubMed

    Tanaka, Naoki; Watari, Akihiro; Tada, Tomoko; Asada, Tomoko; Kunugi, Shigeru; Lee, Yin-Fai; Yamada, Satoshi; Shuto, Kenshiro; Sakaki, Shujiro

    2009-02-01

    We developed a unique method for converting atmospheric aldehyde into alcohol using formaldehyde dehydrogenase from Pseudomonas putida (PFDH) doped in a polymer film. A film of poly(2-methacryloyloxyethylphosphorylcholine-co-n-butyl methacrylate) (PMB), which has a chemical structure similar to that of a biological membrane, was employed for its biocompatibility. A water-incorporated polymer film entrapping PFDH and its cofactor NAD(+) was obtained by drying a buffered solution of PMB, PFDH, and NAD(+). The aldehydes in the air were absorbed into the polymer film and then enzymatically oxidized by PFDH doped in the PMB film. Interestingly, alcohol and carboxylic acid were produced by the enzymatic reaction, indicating that PFDH catalyzes dismutation of aldehyde in the PMB film. Importantly, a PFDH-PMB film catalyzes aldehyde degradation without consuming the nucleotide cofactor, thereby allowing repeated use of the film. The activity of PFDH in the PMB film was higher than that in other common water-soluble polymers, suggesting that the hydrational state in a phospholipid polymer matrix is suitable for enzymatic activity.

  15. Analysis of endogenous aldehydes in human urine by static headspace gas chromatography-mass spectrometry.

    PubMed

    Serrano, María; Gallego, Mercedes; Silva, Manuel

    2016-03-11

    Endogenous aldehydes (EAs) generated during oxidative stress and cell processes are associated with many pathogenic and toxicogenic processes. The aim of this research was to develop a solvent-free and automated analytical method for the determination of EAs in human urine using a static headspace generator sampler coupled with gas chromatography-mass spectrometry (HS-GC-MS). Twelve significant EAs used as markers of different biochemical and physiological processes, namely short- and medium-chain alkanals, α,β-unsaturated aldehydes and dicarbonyl aldehydes have been selected as target analytes. Human urine samples (no dilution is required) were derivatized with O-2,3,4,5,6-pentafluorobenzylhydroxylamine in alkaline medium (hydrogen carbonate-carbonate buffer, pH 10.3). The HS-GC-MS method developed renders an efficient tool for the sensitive and precise determination of EAs in human urine with limits of detection from 1 to 15ng/L and relative standard deviations, (RSDs) from 6.0 to 7.9%. Average recoveries by enriching urine samples ranged between 92 and 95%. Aldehydes were readily determined at 0.005-50μg/L levels in human urine from healthy subjects, smokers and diabetic adults.

  16. The acid free asymmetric intermolecular α-alkylation of aldehydes in fluorinated alcohols.

    PubMed

    Xiao, Jian; Zhao, Kai; Loh, Teck-Peng

    2012-04-11

    The acid free asymmetric intermolecular α-alkylation of aldehydes with alcohols has been discovered using trifluoroethanol as solvent. This unprecedented system affords the enantioenriched functionalized primary alcohols (after NaBH(4) reduction) in high yields and good to excellent enantioselectivities with wide substrate scope in the absence of any acid additive.

  17. Inhibitory effects of Ruta graveolens L. extract on guinea pig liver aldehyde oxidase.

    PubMed

    Pirouzpanah, Saieed; Saieed, Pirouzpanah; Rashidi, Mohammad Reza; Reza, Rashidi Mohammad; Delazar, Abbas; Abbas, Delazar; Razavieh, Seyyed-Vali; Seyyedvali, Razavieh; Hamidi, Aliasghar; Aliasghar, Hamidi

    2006-01-01

    Ruta graveolens L. is a flavonoid-containing medicinal plant with various biological properties. In the present study, the effects of R. graveolens extract on aldehyde oxidase, a molybdenum hydroxylase, are investigated. Aldehyde oxidase was partially purified from liver homogenates of mature male guinea pigs by heat treatment and ammonium sulphate precipitation. The total extract was obtained by macerating the aerial parts of R. graveolens in MeOH 70% and the effect of this extract on the enzyme activity was assayed using phenanthridine, vanillin and benzaldehyde as substrates. Quercetin and its glycoside form, rutin were isolated, purified and identified from the extract and their inhibitory effects on the enzyme were investigated. R. graveolens extract exhibited a high inhibition on aldehyde oxidase activity (89-96%) at 100 microg/ml which was comparable with 10 microM of menadione, a specific potent inhibitor of aldehyde oxidase. The IC50 values for the inhibitory effect of extract against the oxidation of benzaldehyde, vanillin and phenanthridine were 10.4, 10.1, 43.2 microg/ml, respectively. Both quercetin and rutin at 10 microM caused 70-96% and 27-52% inhibition on the enzyme activity, respectively. Quercetin was more potent inhibitor than rutin, but both flavonols exerted their inhibitory effects mostly in a linear mixed-type.

  18. Structural and functional analysis of betaine aldehyde dehydrogenase from Staphylococcus aureus.

    PubMed

    Halavaty, Andrei S; Rich, Rebecca L; Chen, Chao; Joo, Jeong Chan; Minasov, George; Dubrovska, Ievgeniia; Winsor, James R; Myszka, David G; Duban, Mark; Shuvalova, Ludmilla; Yakunin, Alexander F; Anderson, Wayne F

    2015-05-01

    When exposed to high osmolarity, methicillin-resistant Staphylococcus aureus (MRSA) restores its growth and establishes a new steady state by accumulating the osmoprotectant metabolite betaine. Effective osmoregulation has also been implicated in the acquirement of a profound antibiotic resistance by MRSA. Betaine can be obtained from the bacterial habitat or produced intracellularly from choline via the toxic betaine aldehyde (BA) employing the choline dehydrogenase and betaine aldehyde dehydrogenase (BADH) enzymes. Here, it is shown that the putative betaine aldehyde dehydrogenase SACOL2628 from the early MRSA isolate COL (SaBADH) utilizes betaine aldehyde as the primary substrate and nicotinamide adenine dinucleotide (NAD(+)) as the cofactor. Surface plasmon resonance experiments revealed that the affinity of NAD(+), NADH and BA for SaBADH is affected by temperature, pH and buffer composition. Five crystal structures of the wild type and three structures of the Gly234Ser mutant of SaBADH in the apo and holo forms provide details of the molecular mechanisms of activity and substrate specificity/inhibition of this enzyme.

  19. Ambient concentrations of aldehydes in relation to Beijing Olympic air pollution control measures

    NASA Astrophysics Data System (ADS)

    Gong, J. C.; Zhu, T.; Hu, M.; Zhang, L. W.; Cheng, H.; Zhang, L.; Tong, J.; Zhang, J.

    2010-08-01

    Aldehydes are ubiquitous constituents of the atmosphere. Their concentrations are elevated in polluted urban atmospheres. The present study was carried out to characterize three aldehydes of most health concern (formaldehyde, acetaldehyde, and acrolein) in a central Beijing site in the summer and early fall of 2008 (from June to October). Measurements were made before, during, and after the Beijing Olympics to examine whether the air pollution control measures implemented to improve Beijing's air quality during the Olympics had any impact on concentrations of the three aldehydes. Average concentrations of formaldehyde, acetaldehyde and acrolein were 29.34 ± 15.12 μg/m3, 27.09 ± 15.74 μg/m3 and 2.32 ± 0.95 μg/m3, respectively, for the entire period of measurements, all being the highest among the levels measured in cities around the world in photochemical smog seasons. Among the three measured aldehydes, only acetaldehyde had a substantially reduced mean concentration during the Olympic air pollution control period compared to the pre-Olympic period. Formaldehyde and acrolein followed the changing pattern of temperature and were each significantly correlated with ozone (a secondary product of photochemical reactions). In contrast, acetaldehyde was significantly correlated with several pollutants emitted mainly from local emission sources (e.g., NO2, CO, and PM2.5). These findings suggest that local direct emissions had a larger impact on acetaldehyde than formaldehyde and acrolein.

  20. Fast determination of aldehyde preservatives by miniaturized capillary electrophoresis with amperometric detection.

    PubMed

    Li, Ying; Chen, Fang; Ge, Jinyuan; Tong, Fanghong; Deng, Zhaoyue; Shen, Fengwu; Gu, Qianxia; Ye, Jiannong; Chu, Qingcui

    2014-02-01

    A novel miniaturized CE with amperometric detection (mini-CE-AD) method has been developed for fast determination of aliphatic aldehyde preservatives, namely formaldehyde and glyoxal, in commodities. After derivatization with an electroactive compound 2-thiobarbituric acid, these two nonelectroactive aldehydes were converted to electroactive adducts, therefore detectable by mini-CE-AD approach. Under the optimum conditions, two aldehydes can be well-separated with the coexisting interferents as well as their homologs (acetaldehyde and methyl-glyoxal), and the LODs (S/N = 3) were achieved at nanogram-per-milliliter level (1.64-2.80 ng/mL) based on the online enrichment method of transient moving chemical reaction boundary. The proposed method has been applied for the analyses of above aldehyde preservatives in different real commodity samples including skincare products, baby lotion, and toothpaste, and the average recoveries were in the range of 94-105%, which should find a wide range of analytical applications as an alternative to conventional and microchip CE approaches.

  1. Dual Lewis Acid/Lewis Base Catalyzed Acylcyanation of Aldehydes: A Mechanistic Study.

    PubMed

    Laurell Nash, Anna; Hertzberg, Robin; Wen, Ye-Qian; Dahlgren, Björn; Brinck, Tore; Moberg, Christina

    2016-03-01

    A mechanistic investigation, which included a Hammett correlation analysis, evaluation of the effect of variation of catalyst composition, and low-temperature NMR spectroscopy studies, of the Lewis acid-Lewis base catalyzed addition of acetyl cyanide to prochiral aldehydes provides support for a reaction route that involves Lewis base activation of the acyl cyanide with formation of a potent acylating agent and cyanide ion. The cyanide ion adds to the carbonyl group of the Lewis acid activated aldehyde. O-Acylation by the acylated Lewis base to form the final cyanohydrin ester occurs prior to decomplexation from titanium. For less reactive aldehydes, the addition of cyanide is the rate-determining step, whereas, for more reactive, electron-deficient aldehydes, cyanide addition is rapid and reversible and is followed by rate-limiting acylation. The resting state of the catalyst lies outside the catalytic cycle and is believed to be a monomeric titanium complex with two alcoholate ligands, which only slowly converts into the product.

  2. Nepetanal and nepetanoate: a new diterpene aldehyde and a benzene derivative ester from Nepeta juncea.

    PubMed

    Hussain, Javid; Jamila, Nargis; Khan, Farman Ullah; Devkota, Krishna Prasad; Shah, M Raza; Anwar, Saeed

    2009-07-01

    One new tricyclic clerodane type diterpene aldehyde nepetanal (1) and one new benzene derivative nepetanoate (2) have been isolated from a plant Nepeta juncea together with two known compounds oleanolic acid (3) and ursolic acid (4). The structures of the isolated compounds were elucidated by means of modern spectroscopic techniques and comparison with literature data.

  3. A general palladium-catalyzed carbonylative synthesis of chromenones from salicylic aldehydes and benzyl chlorides.

    PubMed

    Wu, Xiao-Feng; Wu, Lipeng; Jackstell, Ralf; Neumann, Helfried; Beller, Matthias

    2013-09-01

    Cute CO! An interesting and straightforward procedure for the carbonylative synthesis of chromenones from readily available salicylic aldehydes and benzyl chlorides has been developed (see scheme; DPPP = 1,3-bis(diphenylphosphino)propane). In the presence of a palladium catalyst, various coumarins were produced in good to excellent yields.

  4. Ultrasound assisted direct oxidative esterification of aldehydes and alcohols using graphite oxide and Oxone.

    PubMed

    Mirza-Aghayan, Maryam; Zonoubi, Somayeh; Molaee Tavana, Mahdieh; Boukherroub, Rabah

    2015-01-01

    A sonochemical procedure for direct oxidative esterification of aldehydes and alcohols using graphite oxide and Oxone in an alcoholic solvent is described. Mild reaction conditions, short reaction times, cost-effectiveness, and facile isolation of the products make the present system as a practical method. PMID:24929791

  5. Structural and functional analysis of betaine aldehyde dehydrogenase from Staphylococcus aureus

    PubMed Central

    Halavaty, Andrei S.; Rich, Rebecca L.; Chen, Chao; Joo, Jeong Chan; Minasov, George; Dubrovska, Ievgeniia; Winsor, James R.; Myszka, David G.; Duban, Mark; Shuvalova, Ludmilla; Yakunin, Alexander F.; Anderson, Wayne F.

    2015-01-01

    When exposed to high osmolarity, methicillin-resistant Staphylococcus aureus (MRSA) restores its growth and establishes a new steady state by accumulating the osmoprotectant metabolite betaine. Effective osmoregulation has also been implicated in the acquirement of a profound antibiotic resistance by MRSA. Betaine can be obtained from the bacterial habitat or produced intracellularly from choline via the toxic betaine aldehyde (BA) employing the choline dehydrogenase and betaine aldehyde dehydrogenase (BADH) enzymes. Here, it is shown that the putative betaine aldehyde dehydrogenase SACOL2628 from the early MRSA isolate COL (SaBADH) utilizes betaine aldehyde as the primary substrate and nicotinamide adenine dinucleotide (NAD+) as the cofactor. Surface plasmon resonance experiments revealed that the affinity of NAD+, NADH and BA for SaBADH is affected by temperature, pH and buffer composition. Five crystal structures of the wild type and three structures of the Gly234Ser mutant of SaBADH in the apo and holo forms provide details of the molecular mechanisms of activity and substrate specificity/inhibition of this enzyme. PMID:25945581

  6. APPLICATION OF MULTISPECTRAL TECHNIQUES TO THE PRECISE IDENTIFICATION OF ALDEHYDES IN THE ENVIRONMENT

    EPA Science Inventory

    By using gas chromatography coupled with low- and high-resolution electron impact mass spectrometry, low- and high-resolution chemical ionization mass spectrometry, and Fourier transform infrared spectroscopy, eight straight-chain aldehydes were identified in a water sample taken...

  7. Two new irregular acyclic sesquiterpenes aldehydes from Santolina corsica essential oil.

    PubMed

    Ferrari, Bernard; Tomi, Félix; Richomme, Pascal; Casanova, Joseph

    2005-01-01

    Two isomeric irregular sesquiterpene aldehydes, namely 3,9-dimethyl-6-isopropyl-2(E),7(E),9-decatrienal and 3,9-dimethyl-6-isopropyl-2(Z),7(E),9-decatrienal, were isolated from the essential oil of Santolina corsica and their structures were elucidated by 1D and 2D NMR spectroscopy.

  8. Highly enantioselective Henry reactions of aromatic aldehydes catalyzed by an amino alcohol-copper(II) complex.

    PubMed

    Qin, Dan-Dan; Lai, Wen-Han; Hu, Di; Chen, Zheng; Wu, An-An; Ruan, Yuan-Ping; Zhou, Zhao-Hui; Chen, Hong-Bin

    2012-08-20

    Amino alcohol-Cu(II) catalyst: Highly enantioselective Henry reactions between aromatic aldehydes and nitromethane have been developed. The reactions were catalyzed by an easily available and operationally simple amino alcohol-copper(II) catalyst. In total, 38 substrates were tested and the R-configured products were obtained in good yields with excellent enantioselectivities. PMID:22791567

  9. Asymmetric intramolecular α-cyclopropanation of aldehydes using a donor/acceptor carbene mimetic

    PubMed Central

    Luo, Chaosheng; Wang, Zhen; Huang, Yong

    2015-01-01

    Enantioselective α-alkylation of carbonyl is considered as one of the most important processes for asymmetric synthesis. Common alkylation agents, that is, alkyl halides, are notorious substrates for both Lewis acids and organocatalysts. Recently, olefins emerged as a benign alkylating species via photo/radical mechanisms. However, examples of enantioselective alkylation of aldehydes/ketones are scarce and direct asymmetric dialkylation remains elusive. Here we report an intramolecular α-cyclopropanation reaction of olefinic aldehydes to form chiral cyclopropane aldehydes. We demonstrate that an α-iodo aldehyde can function as a donor/acceptor carbene equivalent, which engages in a formal [2+1] annulation with a tethered double bond. Privileged bicyclo[3.1.0]hexane-type scaffolds are prepared in good optical purity using a chiral amine. The synthetic utility of the products is demonstrated by versatile transformations of the bridgehead formyl functionality. We expect the concept of using α-iodo iminium as a donor/acceptor carbene surrogate will find wide applications in chemical reaction development. PMID:26644194

  10. A new device for formaldehyde and total aldehydes real-time monitoring.

    PubMed

    Sassine, Maria; Picquet-Varrault, Bénédicte; Perraudin, Emilie; Chiappini, Laura; Doussin, Jean François; George, Christian

    2014-01-01

    A new sensitive technique for the quantification of formaldehyde (HCHO) and total aldehydes has been developed in order to monitor these compounds, which are known to be involved in air quality issues and to have health impacts. Our approach is based on a colorimetric method where aldehydes are initially stripped from the air into a scrubbing solution by means of a turning coil sampler tube and then derivatised with 3-methylbenzothiazolinone-2-hydrazone in acid media (pH = -0.5). Hence, colourless aldehydes are transformed into blue dyes that are detected by UV-visible spectroscopy at 630 nm. Liquid core waveguide LCW Teflon® AF-2400 tube was used as innovative optical cells providing a HCHO detection limit of 4 pptv for 100 cm optical path with a time resolution of 15 min. This instrument showed good correlation with commonly used techniques for aldehydes analysis such as DNPH derivatisation chromatographic techniques with off-line and on-line samplers, and DOAS techniques (with deviation below 6%) for both indoor and outdoor conditions. This instrument is associated with simplicity and low cost, which is a prerequisite for indoor monitoring. PMID:23892614

  11. One-pot reductive mono-N-alkylation of aniline and nitroarene derivatives using aldehydes.

    PubMed

    Byun, Eunyoung; Hong, Bomi; De Castro, Kathlia A; Lim, Minkyung; Rhee, Hakjune

    2007-12-01

    One-pot reductive mono-N-alkylation of aniline and nitroarene derivatives using various aldehydes by Pd/C catalyst in aqueous 2-propanol solvent with ammonium formate as in situ hydrogen donor is illustrated. The reaction proceeded smoothly and selectively with excellent yield at room temperature. Our protocol presents a facile, economical, and environmentally benign alternative for reductive amination.

  12. Analysis of carbonaceous biomarkers with the Mars Organic Analyzer microchip capillary electrophoresis system: aldehydes and ketones.

    PubMed

    Stockton, Amanda M; Tjin, Caroline Chandra; Huang, Grace L; Benhabib, Merwan; Chiesl, Thomas N; Mathies, Richard A

    2010-11-01

    A microchip CE method is developed for the analysis of two oxidized forms of carbon, aldehydes and ketones, with the Mars Organic Analyzer (MOA). Fluorescent derivitization is achieved in ∼ 15 min by hydrazone formation with Cascade Blue hydrazide in 30 mM borate pH 5-6. The microchip CE separation and analysis method is optimized via separation in 30 mM borate buffer, pH 9.5, at 20°C. A carbonyl standard consisting of ten aldehydes and ketones found in extraterrestrial matter is successfully separated; the resulting LOD depends on the reactivity of the compound and range from 70 pM for formaldehyde to 2 μM for benzophenone. To explore the utility of this method for analyzing complex samples, analyses of several fermented beverages are conducted, identifying ten aldehydes and ketones ranging from 30 nM to 5 mM. A Martian regolith simulant sample, consisting of a basalt matrix spiked with soluble ions and acetone, is designed and analyzed, but acetone is found to have a limited detectable lifetime under simulant Martian conditions. This work establishes the capability of the MOA for studying aldehydes and ketones, a critical class of oxidized organic molecules of interest in planetary and in terrestrial environmental and health studies. PMID:20967779

  13. Approximate error conjugation gradient minimization methods

    DOEpatents

    Kallman, Jeffrey S

    2013-05-21

    In one embodiment, a method includes selecting a subset of rays from a set of all rays to use in an error calculation for a constrained conjugate gradient minimization problem, calculating an approximate error using the subset of rays, and calculating a minimum in a conjugate gradient direction based on the approximate error. In another embodiment, a system includes a processor for executing logic, logic for selecting a subset of rays from a set of all rays to use in an error calculation for a constrained conjugate gradient minimization problem, logic for calculating an approximate error using the subset of rays, and logic for calculating a minimum in a conjugate gradient direction based on the approximate error. In other embodiments, computer program products, methods, and systems are described capable of using approximate error in constrained conjugate gradient minimization problems.

  14. Immunization of newborns with bacterial conjugate vaccines.

    PubMed

    van den Biggelaar, Anita H J; Pomat, William S

    2013-05-17

    Bacterial conjugate vaccines are based on the principle of coupling immunogenic bacterial capsular polysaccharides to a carrier protein to facilitate the induction of memory T-cell responses. Following the success of Haemophilus influenzae type b conjugate vaccines in the 1980s, conjugate vaccines for Streptococcus pneumoniae and Neisseria meningitidis infections were developed and proven to be effective in protecting children against invasive disease. In this review, the use of conjugate vaccines in human newborns is discussed. Neonatal Haemophilus influenzae type b and pneumococcal conjugate vaccination schedules have been trialed and proven to be safe, with the majority of studies demonstrating no evidence for the induction of immune tolerance. Whether their neonatal administration also results in an earlier induction of clinical protection in the first 2-3 critical months of life is still to be demonstrated. PMID:22728221

  15. Campholenic aldehyde ozonolysis: a possible mechanism for the formation of specific biogenic secondary organic aerosol constituents

    NASA Astrophysics Data System (ADS)

    Kahnt, A.; Iinuma, Y.; Mutzel, A.; Böge, O.; Claeys, M.; Herrmann, H.

    2013-08-01

    In the present study, campholenic aldehyde ozonolysis was performed to investigate pathways leading to specific biogenic secondary organic aerosol (SOA) marker compounds. Campholenic aldehyde, a known α-pinene oxidation product, is suggested to be a key intermediate in the formation of terpenylic acid upon α-pinene ozonolysis. It was reacted with ozone in the presence and absence of an OH radical scavenger leading to SOA formation with a yield of 0.75 and 0.8, respectively. The resulting oxidation products in the gas and particle phases were investigated employing a denuder/filter sampling combination. Gas-phase oxidation products bearing a carbonyl group, which were collected by the denuder, were derivatised with 2,4-dinitrophenylhydrazine (DNPH) followed by Liquid Chromatography/negative ion Electrospray Ionisation Time-of-Flight Mass Spectrometry analysis and were compared to the gas-phase compounds detected by online Proton-Transfer-Reaction Mass Spectrometry. Particle-phase products were also analysed, directly or after DNPH derivatisation, to derive information about specific compounds leading to SOA formation. Among the detected compounds, the aldehydic precursor of terpenylic acid was identified and its presence was confirmed in ambient aerosol samples from the DNPH derivatisation, accurate mass data, and MS2 and MS3 fragmentation studies. Furthermore, the present investigation sheds light on a reaction pathway leading to the formation of terpenylic acid, involving α-pinene, α-pinene oxide, campholenic aldehyde, and terpenylic aldehyde. Additionally, the formation of diaterpenylic acid acetate could be connected to campholenic aldehyde oxidation. The present study also provides insights into the source of other highly functionalised oxidation products (e.g. m/z 201, C9H14O5 and m/z 215, C10H16O5), which have been observed in ambient aerosol samples and smog chamber-generated monoterpene SOA. The m/z 201 and 215 compounds were tentatively identified as a

  16. Campholenic aldehyde ozonolysis: a mechanism leading to specific biogenic secondary organic aerosol constituents

    NASA Astrophysics Data System (ADS)

    Kahnt, A.; Iinuma, Y.; Mutzel, A.; Böge, O.; Claeys, M.; Herrmann, H.

    2014-01-01

    In the present study, campholenic aldehyde ozonolysis was performed to investigate pathways leading to specific biogenic secondary organic aerosol (SOA) marker compounds. Campholenic aldehyde, a known α-pinene oxidation product, is suggested to be a key intermediate in the formation of terpenylic acid upon α-pinene ozonolysis. It was reacted with ozone in the presence and absence of an OH radical scavenger, leading to SOA formation with a yield of 0.75 and 0.8, respectively. The resulting oxidation products in the gas and particle phases were investigated employing a denuder/filter sampling combination. Gas-phase oxidation products bearing a carbonyl group, which were collected by the denuder, were derivatised by 2,4-dinitrophenylhydrazine (DNPH) followed by liquid chromatography/negative ion electrospray ionisation time-of-flight mass spectrometry analysis and were compared to the gas-phase compounds detected by online proton-transfer-reaction mass spectrometry. Particle-phase products were also analysed, directly or after DNPH derivatisation, to derive information about specific compounds leading to SOA formation. Among the detected compounds, the aldehydic precursor of terpenylic acid was identified and its presence was confirmed in ambient aerosol samples from the DNPH derivatisation, accurate mass data, and additional mass spectrometry (MS2 and MS3 fragmentation studies). Furthermore, the present investigation sheds light on a reaction pathway leading to the formation of terpenylic acid, involving α-pinene, α-pinene oxide, campholenic aldehyde, and terpenylic aldehyde. Additionally, the formation of diaterpenylic acid acetate could be connected to campholenic aldehyde oxidation. The present study also provides insights into the source of other highly functionalised oxidation products (e.g. m / z 201, C9H14O5 and m / z 215, C10H16O5), which have been observed in ambient aerosol samples and smog chamber-generated monoterpene SOA. The m / z 201 and 215

  17. Critical role of aldehydes in cigarette smoke-induced acute airway inflammation

    PubMed Central

    2013-01-01

    Background Cigarette smoking (CS) is the most important risk factor for COPD, which is associated with neutrophilic airway inflammation. We hypothesize, that highly reactive aldehydes are critical for CS-induced neutrophilic airway inflammation. Methods BALB/c mice were exposed to CS, water filtered CS (WF-CS) or air for 5 days. Levels of total particulate matter (TPM) and aldehydes in CS and WF-CS were measured. Six hours after the last exposure, inflammatory cells and cytokine levels were measured in lung tissue and bronchoalveolar lavage fluid (BALF). Furthermore, Beas-2b bronchial epithelial cells were exposed to CS extract (CSE) or WF-CS extract (WF-CSE) in the absence or presence of the aldehyde acrolein and IL-8 production was measured after 24 hrs. Results Compared to CS, in WF-CS strongly decreased (CS; 271.1 ± 41.5 μM, WF-CS; 58.5 ± 8.2 μM) levels of aldehydes were present whereas levels of TPM were only slightly reduced (CS; 20.78 ± 0.59 mg, WF-CS; 16.38 ± 0.36 mg). The numbers of mononuclear cells in BALF (p<0.01) and lung tissue (p<0.01) were significantly increased in the CS- and WF-CS-exposed mice compared to air control mice. Interestingly, the numbers of neutrophils (p<0.001) in BALF and neutrophils and eosinophils (p<0.05) in lung tissue were significantly increased in the CS-exposed but not in WF-CS-exposed mice as compared to air control mice. Levels of the neutrophil and eosinophil chemoattractants KC, MCP-1, MIP-1α and IL-5 were all significantly increased in lung tissue from CS-exposed mice compared to both WF-CS-exposed and air control mice. Interestingly, depletion of aldehydes in WF-CS extract significantly reduced IL-8 production in Beas-2b as compared to CSE, which could be restored by the aldehyde acrolein. Conclusion Aldehydes present in CS play a critical role in inflammatory cytokine production and neutrophilic- but not mononuclear airway inflammation. PMID:23594194

  18. Catalytic conjugate additions of geminal bis(sulfone)s: expanding the chemistry of sulfones as simple alkyl anion equivalents.

    PubMed

    Landa, Aitor; Puente, Angel; Santos, J Ignacio; Vera, Silvia; Oiarbide, Mikel; Palomo, Claudio

    2009-11-01

    The value of cyclic gem-bis(sulfone) 4 as a simple alkyl nucleophile equivalent in catalytic C-C bond-forming reactions is demonstrated. The 1,4-type nucleophilic additions of bis(sulfone) 4 to alpha,beta-unsaturated ketones take place by assistance of catalytic guanidine base. On the other hand, pyrrolidines are able to catalyze the conjugate addition of 4 to both enones and enals, likely by means of iminium ion activation. Upon exploration of the best chiral pyrrolidine catalyst, it has been found that the addition of 4 to enals catalyzed by diphenylprolinol silyl ether 10 proceeds with very high enantioselectivity (beta-aryl-substituted enals >95% ee; beta-alkyl substituted enals up to 94% ee; ee = enantiomeric excess). Further reductive desulfonation of adducts gives rise to the corresponding beta-methyl aldehydes, as well as the derived alcohols, acetals, and methyl esters after simple (Mg, MeOH) well-established protocols. Application of the procedure to the synthesis of biologically relevant phenethyl building blocks is shown. Most interestingly, alpha-alkylation of initially obtained bis(sulfone) adducts can be done even with less reactive alkylating reagents, such as long linear-chain or branched-chain alkyl halides. Accordingly, upon the desulfonation process, a general, experimentally simple and highly enantioselective access to beta-branched aldehydes, alcohols, or esters is possible. Further exploration of the method includes the use of chiral alpha,beta-unsaturated aldehydes derived from citronellal as the Michael acceptor partners. In these instances, the sense of the conjugate addition of 4 is controlled by the chirality of the pyrrolidine catalyst, thus allowing for a stereochemically predictable access to 1,3-dimethyl arrays, such as those present in deoxygenated polyketide-type natural products. The intramolecular variation of this technology by using doubly unsaturated aldehyde-ester 22 illustrated the site selectivity of the procedure and its

  19. Cytosolic pressure provides a propulsive force comparable to actin polymerization during lamellipod protrusion

    PubMed Central

    Manoussaki, Daphne; Shin, William D.; Waterman, Clare M.; Chadwick, Richard S.

    2015-01-01

    Does cytosolic pressure facilitate f-actin polymerization to push the leading edge of a cell forward during self-propelled motion? AFM force-distance (f-d) curves obtained from lamellipodia of live cells often exhibit a signal from which the tension, bending modulus, elastic modulus and thickness in the membrane-cortex complex can be estimated close to the contact point. These measurements permit an estimate of the cytosolic pressure via the canonical Laplace force balance. The deeper portion of the f-d curve allows estimation of the bulk modulus of the cytoskeleton after removal of the bottom effect artifact. These estimates of tension, pressure, cortex thickness and elastic moduli imply that cytosolic pressure both pushes the membrane forward and compresses the actin cortex rearward to facilitate f-actin polymerization. We also estimate that cytosolic pressure fluctuations, most likely induced by myosin, provide a propulsive force comparable to that provided by f-actin polymerization in a lamellipod. PMID:26197304

  20. Negative inotropic drugs alter indexes of cytosolic [Ca(2+)]-left ventricular pressure relationships after ischemia.

    PubMed

    Camara, Amadou K S; Chen, Qun; Rhodes, Samhita S; Riess, Matthias L; Stowe, David F

    2004-08-01

    Negative inotropic agents may differentially modulate indexes of cytosolic [Ca(2+)]-left ventricular (LV) pressure (LVP) relationships when given before and after ischemia. We measured and calculated [Ca(2+)], LVP, velocity ratios [[(d[Ca(2+)]/dt(max))/(dLVP/dt(max)); VR(max)] and [(d[Ca(2+)]/dt(min))/(dLVP/dt(min)); VR(min)