Presence Of Trimethylamine Oxide Research Articles

The greening reaction of skipjack tuna (Katsuwonus pelamis) metmyoglobin promoted by free cysteine during thermal treatment.

BackgroundTuna muscle greening is a problem that occurs after heating. A hypothesis has been postulated to address this problem, involving a conserved Cys residue at position 10 (Cys-10) present on tuna myoglobin (Mb) that is exposed during the thermic treatment, forming a disulfide bond with free cysteine (Cys) in the presence of trimethylamine oxide (TMAO), resulting in the greening of the tuna Mb.MethodsWe present a study using skipjack tuna (Katsuwonus pelamis) metmyoglobin (MbFe(III)-H2O) where the effect of free Cys (1–6 mM), TMAO (1.33 mM), and catalase on the greening reaction (GR) was monitored by UV-vis spectrometry during thermal treatment at 60 °C for 30 min. Moreover, the participation of Cys-10 on the GR was evaluated after its blocking with N-ethymaleimide.ResultsThe GR occurred in tuna MbFe(III)-H2O after heat treatment with free Cys, forming sulfmyoglobin (MbFe(II)-S) as the responsible pigment for the tuna greening. However, the rate constants of MbFe(II)-S production depended on Cys concentration (up to 4 mM) and occurred regardless of the TMAO presence. We postulate that two consecutive reactions involve an intermediate ferrylmyoglobin (promoted by H2O2) species with a subsequent MbFe(II)-S formation since the presence of catalase fosters the reduction of the rate reaction. Moreover, GR occurred even with blocked Cys-10 residues in tuna Mb and horse Mb (without Cys in its sequence).DiscussionWe found that GR is not exclusive to tuna Mb´s, and it can be promoted in other muscle systems. Moreover, Cys and thermal treatment are indispensable for promoting this pigmentation anomaly.

The reactions of [(μ-H)M3(CO)9(CCSiMe3)] (M=Fe, Ru) with thiols: Cleavage of M-M and formation of M-S bonds in isomeric structures

The reactions of the acetylide trinuclear derivatives [(μ-H)M3(CO)9(CCSiMe3)] (M=Fe, Ru) with the thiols C6H5SH and C6F5SH were carried out. Both reactions lead to the formation of products where cleavage of M-M bonds have occurred. In the case of the iron complex, two products are obtained in the reactions with both thiols: a trinuclear complex of formula [Fe3(CO)9(CCSiMe3)(SR)] (R=C6H5 and C6F5) and a dinuclear compound [Fe2(CO)6(CCSiMe3)(SR) (R=C6H5 and C6F5) which is found as anti and syn isomers in the case of C6H5 and only as the anti isomer in the fluorinated thiol. The reaction with the ruthenium complex under the same conditions gives only decomposition products, but when the reaction with pentafluorothiophenol is carried out in the presence of trimethylamine oxide, total cleavage of M-M bonds takes place to form a mononuclear complex [Ru(CO)3(SC6F5)3]. Spectroscopic and structural characterization of the iron complexes is given. Two isomeric crystal structures were obtained for the trinuclear fluorinated complex.

Biomarkers of whale shark health: a metabolomic approach.

In a search for biomarkers of health in whale sharks and as exploration of metabolomics as a modern tool for understanding animal physiology, the metabolite composition of serum in six whale sharks (Rhincodon typus) from an aquarium collection was explored using 1H nuclear magnetic resonance (NMR) spectroscopy and direct analysis in real time (DART) mass spectrometry (MS). Principal components analysis (PCA) of spectral data showed that individual animals could be resolved based on the metabolite composition of their serum and that two unhealthy individuals could be discriminated from the remaining healthy animals. The major difference between healthy and unhealthy individuals was the concentration of homarine, here reported for the first time in an elasmobranch, which was present at substantially lower concentrations in unhealthy whale sharks, suggesting that this metabolite may be a useful biomarker of health status in this species. The function(s) of homarine in sharks remain uncertain but it likely plays a significant role as an osmolyte. The presence of trimethylamine oxide (TMAO), another well-known protective osmolyte of elasmobranchs, at 0.1–0.3 mol L−1 was also confirmed using both NMR and MS. Twenty-three additional potential biomarkers were identified based on significant differences in the frequency of their occurrence between samples from healthy and unhealthy animals, as detected by DART MS. Overall, NMR and MS provided complementary data that showed that metabolomics is a useful approach for biomarker prospecting in poorly studied species like elasmobranchs.

Shewanella oneidensis: a new and efficient System for Expression and Maturation of heterologous [Fe-Fe] Hydrogenase from Chlamydomonas reinhardtii

BackgroundThe eukaryotic green alga, Chlamydomonas reinhardtii, produces H2 under anaerobic conditions, in a reaction catalysed by a [Fe-Fe] hydrogenase HydA1. For further biochemical and biophysical studies a suitable expression system of this enzyme should be found to overcome its weak expression in the host organism. Two heterologous expression systems used up to now have several advantages. However they are not free from some drawbacks. In this work we use bacterium Shewanella oneidensis as a new and efficient system for expression and maturation of HydA1 from Chlamydomonas reinhardtii.ResultsBased on codon usage bias and hydrogenase maturation ability, the bacterium S. oneidensis, which possesses putative [Fe-Fe] and [Ni-Fe] hydrogenase operons, was selected as the best potential host for C. reinhardtii [Fe-Fe] hydrogenase expression. Hydrogen formation by S. oneidensis strain AS52 (ΔhydAΔhyaB) transformed with a plasmid bearing CrHydA1 and grown in the presence of six different substrates for anaerobic respiration was determined. A significant increase in hydrogen evolution was observed for cells grown in the presence of trimethylamine oxide, dimethylsulfoxide and disodium thiosulfate, showing that the system of S. oneidensis is efficient for heterologous expression of algal [Fe-Fe] hydrogenase.ConclusionIn the present work a new efficient system for heterologous expression and maturation of C. reinhardtii hydrogenase has been developed. HydA1 of C. reinhardtii was purified and shown to contain 6 Fe atoms/molecule of protein, as expected. Using DMSO, TMAO or thiosulfate as substrates for anaerobic respiration during the cell growth, 0.4 – 0.5 mg l-1(OD600 = 1) of catalytically active HydA1 was obtained with hydrogen evolution rate of ~700 μmol H2 mg-1 min-1.

Aerobic TMAO respiration in Escherichia coli

In the absence of oxygen, Escherichia coli can use alternative exogenous electron acceptors, including trimethylamine oxide (TMAO), to generate energy. In this study, we showed that in contrast to the other anaerobic respiratory systems, the TMAO reductase (Tor) system was expressed during both aerobiosis and anaerobiosis. By using a torA-lacZ fusion and quantitative reverse transcription polymerase chain reaction, we established that the torCAD operon encoding the Tor system was induced in the presence of TMAO mainly during exponential phase, and that optimal induction required a certain level of DNA supercoiling. We also showed that the presence of oxygen prevented neither the biogenesis of the Tor system nor the reduction of TMAO. The physiological role of TMAO reduction during aerobiosis has not been yet established, but our experiments suggest that alkaline TMA production could enhance the growth conditions by increasing the pH of the culture.

Trimethylamine oxide suppresses stress-induced alteration of organic anion transport in choroid plexus

The effect of physicochemical stress on organic anion transport across the vertebrate blood-cerebrospinal fluid (CSF) barrier in the presence and absence of an endogenous cytoprotectant, trimethylamine oxide (TMAO), was investigated in isolated IVth choroid plexus (CP) of spiny dogfish shark (Squalus acanthias), an animal with naturally high levels of TMAO ( approximately 70 mmol l(-1)). Active transepithelial absorption of the organic anion, 2,4-dichlorophenoxyacetic acid (2,4-D), by IVth CP mounted in Ussing chambers was measured after in vitro stress, and a marker for the cellular stress response, inducible heat shock protein 70 (Hsp70), was assayed by immunoblot analysis. Transient heat stress (a shift from the normal 13.5 degrees C to 23.5 degrees C for 1 h) decreased 2,4-D transport by approximately 66%; however, the same stress minus TMAO (isosmotic replacement with urea) had no effect on transport rate. In the absence of TMAO, stress-induced Hsp70 accumulation was more than double that seen in the presence of TMAO. Likewise, exposure to 50 micromol l(-1) Zn for 6 h induced a twofold greater Hsp70 accumulation in the absence of TMAO than in its presence, and the higher Hsp70 level was associated with a higher 2,4-D transport rate. Heat stress and 50 micromol l(-1) Zn also induced more pronounced increases in Hsp70 mRNA in the absence of TMAO. Thus, the cellular stress response can significantly alter CP organic anion transport capacity, and an endogenous osmolyte can suppress that response.

The importance of cluster fragmentation in the catalytic hydrogenation of phenylacetylene by PtRu 5 carbonyl cluster complexes

PtRu 5 ( CO ) 13 ( PBu 3 t ) ( μ 3 - PhC 2 H ) ( μ 5 - C ) ( 2 ) has been shown to be a catalyst precursor for the hydrogenation of PhC 2H to styrene and ethylbenzene. Three new organometallic products have been found in the catalyst solutions. These are Ru 5 ( CO ) 12 ( μ 5 - C ) [ PtPBu 3 t ] ( μ 3 - PhC 2 H ) ( μ - H ) 2 ( 4 ) , Pt ( PBu 3 t ) ( PhC 2 H ) ( CO ) ( 5 ) , and Ru 5(CO) 11(μ 4-CCHCPh)(μ 4-HC 2Ph)(μ 3-HC 2Ph) ( 6). Compounds 4– 6 have been synthesized independently and structurally characterized and each one has been tested independently for its ability to produce hydrogenation of PhC 2H catalytically. Compound 4 contains an open square-pyramidal cluster of five ruthenium atoms with one platinum atom bridging an edge of the cluster. It is structurally related to 2 but contains one less CO ligand and two hydrido ligands formed by the addition of one equivalent of hydrogen to the metal cluster. It can be obtained directly from 2 by reaction with hydrogen in the presence of trimethylamine oxide. Compound 5 is a tricoordinated mononuclear platinum complex containing one PBu 3 t ligand, one CO ligand and one μ 2-PhC 2H ligand. Compound 5 can be obtained directly from Pt ( PBu 3 t ) 2 by reaction with PhC 2H under an atmosphere of CO. Compound 6 was obtained from the reaction of Ru 5(CO) 15(μ 5-C) with PhC 2H in the presence of UV–Vis irradiation. Compound 6 contains three equivalents of PhC 2H; one is present as triply bridging PhC 2H ligand; one is a quadruply bridging ligand; the third one has formed a bond to the carbido ligand in the center of the metal cluster to form a novel tetra-metallated allyl ligand. Compound 5 has the highest catalytic activity of all three compounds and is believed to be responsible for the vast majority of the catalytic hydrogenation produced from the solutions of 2. Compound 4 is transformed into 5 under the conditions of catalysis.

Novel Approach to Mixed Group 15/16 Element Ligands-Formation of Unusual Trichalcogenophosphonato Ligands in Mixed Fe/Cr Clusters.

Trithiophosphonato and triselenophosphonato ligands containing mixed Fe/Cr clusters have been synthesized from the reaction of [Fe3 (CO)9 (μ3 -Y)2 ] (Y=S or Se) with [CpCr(CO)2 (η3 -P3 ] in the presence of trimethylamine oxide. This novel approach leads to new clusters containing the first examples of P(S)S2 and P(Se)Se2 ligands in complexed forms.

Effects of urea and trimethylamine N-oxide on fluidity of liposomes and membranes of an elasmobranch.

The effects on membrane fluidity of two solutes of biological importance in elasmobranch fishes, urea and trimethylamine oxide (TMAO), were determined using elasmobranch red blood cell plasma membranes and artificial liposomes. Fluorescence polarizations of three probes with differing sites of insertion (1, 6-diphenylhexatriene, cis-parinaric acid, and trans-parinaric acid) were used to study the effects of physiological levels of urea (400 mM) and TMAO (200 mM) separately and together in a 2:1 urea:TMAO ratio (400 mM:200 mM). In the elasmobranch erythrocyte membrane, there was a trend toward an increase in the order of the gel-phase domains when treated with urea, although this was not statistically significant. This effect was counteracted by the presence of TMAO. To determine if the organic solutes were acting directly on the membrane lipids or on the integral proteins, phase-transition profiles of protein-free dipalmitoyl phosphatidylcholine liposomes were determined. These profiles showed that urea again increased the order of the gel-phase domains of the bilayer; however, this effect was not counteracted by the presence of TMAO. We suggest that the increased order in the gel-phase domains may be an indirect effect of a decrease in the order of the fluid-phase domains. This increase in fluidity may be due either to a disruptive effect of urea on the hydrophobic core of the membrane or to indirect effects mediated by changes in the integral membrane proteins. This study is the first to demonstrate that urea and TMAO may act as counteracting solutes in the elasmobranch erythrocyte membrane and that the counteraction appears to be at the level of the integral proteins rather than the membrane lipids.

ChemInform Abstract: Characterization of Properties of the Rigid Tridentate Chelate Ligand N,N′‐Bis(diphenylphosphino)‐2,6‐diaminopyridine and N,N‐Bis(diphenylphosphino)‐2‐aminopyridine with Transition Metals of the Chromium Group.

AbstractThe 1:1 molar reaction of the 2,6‐bis(phosphinoamino)pyridine (I) with the hexacarbonyls (II) in the presence of trimethylamine oxide gives the bidentate ligand complexes (III) ((IIIb): space group C2/c, Z = 8) in addition to the trimethylamine complexes (IV).

Oxygen-atom-transfer reactions to metal carbonyls. Kinetics and mechanism of CO substitution of M(CO)5 (M = Fe, Ru, Os) in the presence of trimethylamine oxide

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOxygen-atom-transfer reactions to metal carbonyls. Kinetics and mechanism of CO substitution of M(CO)5 (M = Fe, Ru, Os) in the presence of trimethylamine oxideJiankun Shen, Yici Gao, Qizhen Shi, and Fred BasoloCite this: Organometallics 1989, 8, 9, 2144–2147Publication Date (Print):September 1, 1989Publication History Published online1 May 2002Published inissue 1 September 1989https://doi.org/10.1021/om00111a008RIGHTS & PERMISSIONSArticle Views306Altmetric-Citations38LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (493 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Oxygen atom transfer to metal carbonyls. Kinetics and mechanism of carbon monoxide substitution reactions of M3(CO)11L (M = iron, ruthenium, osmium) in the presence of trimethylamine oxide

Etude de la substitution d'un carbonyle par AsPh 3 , SbPh 3 et des phosphines tertiaires. Comparaison des constantes cinetiques d'apres la nature du substituant, la concentration en (CH 3 ) 3 NO et parametres d'activattion

Additions and Corrections - Oxygen atom transfer reactions to metal carbonyls. Kinetics and mechanism of carbon monoxide substitution reactions of M(CO)6 (M = chromium, molybdenum, tungsten) in the presence of trimethylamine oxide [Erratum to document cited in CA107(5):38888M

Additions and Corrections - Oxygen atom transfer reactions to metal carbonyls. Kinetics and mechanism of carbon monoxide substitution reactions of M(CO)6 (M = chromium, molybdenum, tungsten) in the presence of trimethylamine oxide [Erratum to document cited in CA107(5):38888M

Oxygen atom transfer reaction to metal carbonyls. Kinetics and mechanism of carbonyl-substitution reactions of Mo(CO)5L in the presence of trimethylamine oxide

Oxygen atom transfer reaction to metal carbonyls. Kinetics and mechanism of carbonyl-substitution reactions of Mo(CO)5L in the presence of trimethylamine oxide

Oxygen atom transfer reactions to metal carbonyls. Kinetics and mechanism of carbon monoxide substitution reactions of M(CO)6 (M = chromium, molybdenum, tungsten) in the presence of trimethylamine oxide

Cinetique des reactions de M(CO) 6 avec Me 3 NO en presence ou non de PPh 3 . Les vitesses sont du 1er ordre par rapport aux 2 reactifs, mais d'ordre 0 par rapport a PPh 3

Stabilization of tocopherol by three components synergism involving tocopherol, phospholipid and amino compound

AbstractThe effects of minor‐component phospholipids, sterols, trimethylamine oxide (TMAO) and tri‐n‐octylamine (TOA) on the stabilization of γ‐tocopherol (γ‐Toc) were investigated during the autoxidation of methyl linoleate (ML). On autoxidation of lard containing γ‐Toc and TMAO, γ‐Toc was rapidly oxidized and decreased to the 50–60% level in the initial stage of reaction. After that, the total amounts of γ‐Toc and its reducing dimers, γ‐Toc diphenyl ether dimer, γ‐Toc biphenyl dimer (H), and γ‐Toc biphenyl dimer (L), formed from oxidized γ‐Toc, were maintained at a higher level for a longer time. These results indicate the presence of minor components contribution to the stability of γ‐Toc. Therefore, three‐component synergism involving γ‐Toc, TMAO and each phospholipid was tested using ML as substrate. Accordingly, phosphatidyl ethanolamine (PE), phosphatidyl serine (PS), phosphatidyl inositol and phosphatidic acid showed a marked synergistic effect: PS especially inhibited the oxidation of γ‐Toc. More than 0.02% of PE was found to keep a constant level of the residual amount of γ‐Toc and to retared the formation of γ‐Toc biphenyl dimers, which are perferential in the presence of TMAO. Phosphatidyl choline (PC), phosphatidyl glycerol and sterols did not show such an effect. However, PC synergized with TOA for stabilizing γ‐Toc in autoxidizing ML.

The Induction and Location of Trimethylamine-N-oxide Reductase in Alteromonas sp. NCMB 400

Trimethylamine-N-oxide (TMAO) supported anoxic growth in the non-fermentative marine bacterium Alteromonas sp. NCMB 400 and was reduced quantitatively to trimethylamine. The properties of TMAO reductase were those expected of a terminal reductase in anaerobic respiration. The enzyme was induced in the presence of trimethylamine oxide, repressed at high oxygen tensions and derepressed under anaerobic conditions. The cellular location of TMAO reductase was investigated by determining its distribution with respect to enzymes in cellular fractions prepared after lysozyme/EDTA treatment. A spheroplasting technique was developed, based on the method of Birdsell & Cota-Robles, that gave a high yield of intact spheroplasts from cells of marine alteromonads, and marker enzyme distribution indicated a clean fractionation. TMAO reductase was located in the periplasmic fraction, but it was released less readily than alkaline phosphatase; full release required EDTA treatment. The results are consistent with the role of TMAO as a terminal electron acceptor for anoxic growth, and the location of TMAO reductase does not preclude the possibility that TMAO reduction is linked to enerav conservation.

Biochemical Ecology of Psychrotrophic Strains of Vibrio anguillarum Isolated from Outbreaks of Vibriosis at Low Temperature

Summary Four strains of the fish pathogen Vibrio anguillarum have been isolated from rainbow trout ( Salmo trutta ), salmon ( Salmo salar ), coalfish ( Gadus virens ) and eel ( Anguilla anguilla ) kept captive at water temperatures of 1–4°C for aquaculture or other purposes in the vicinity of Tromso, Norway. Biochemically, they all closely resemble a reference strain, V. anguillarum NCMB 6. The only important exception was that our strains have lower cardinal temperatures for growth, namely 0°C (minimum), 15–18°C (optimum) and below 30°C (maximum), as opposed to an optimum of 30°C and a maximum of 30–40°C, respectively, for the reference strain. The 4 isolates grew optimally in media containing 2% NaCl, with outer limits for growth at 0.5% and 5% NaCl. The viability was quickly lost in nutrient media without inorganic salt, in membrane-filtered seawater and by freezing or freeze-drying. The outer pH limits for growth were 5 and 9, respectively. Our strains showed enhanced anaerobic growth yields in the presence of trimethylamine oxide (TMAO). When examined with immunochemical methods all the strains, including the reference strain, showed serological cross-reaction, but they clearly differed in antigenic structure.

Synthesis, stereodynamics, and reactivity of isonitrile derivatives of dodecacarbonyltetrairidium

Abstract The reaction of Ir 4( CO) 12 with t-BuNC or MeNC in the presence of trimethylamine oxide in refluxing tetrahydrofuran provides the substituted iridium clusters Ir 4 (CO) 12-x (RNC) x ] (χ  14; R  t-Bu, Me). The infrared and 13 C NMR spectra of these molecules indicate that most of them adopt structures related to Ir 4 (CO) 12 , i.e., they have only terminal carbonyl ligands. The variable temperature 13 C NMR spectra for Ir 4 (CO) 11 (t-BuNC) establish a carbonyl scrambling process which is the formal inverse of the C 3v → T d scrambling mechanism proposed for Rh 4 (CO) 12 . The kinetics of substitution of Ir 4 (CO) 12 by t-BuNC have been studied. Each substitution step occurs by a ligand-dependent, overall second-order reaction at a rate much greater than for substitution by PPh 3 . The observed differences between t-BuNC and PPh 3 , can be rationalized on the basis of steric differences between the two ligands.

Trimethylamine oxide: a terminal electron acceptor in anaerobic respiration of bacteria.

Trimethylamine oxide (TMAO) stimulated both the anaerobic growth rate and the growth yield of Proteus NTHC 153. The molar growth yield from glucose and pyruvate in tryptone/yeast extract medium doubled in the presence of TMAO, and the organism grew anaerobically on the non-fermentable substrates L-lactate and formate when TMAO was added to the medium. We conclude that TMAO stimulated growth by serving as a terminal electron acceptor in an oxidative phosphorylation process.