Application and Mechanism of Malonic Acid as a Green Alternative for Protein-Crosslinking

Formaldehyde fixation is the main method for crosslinking cellular proteins prior to their usage in immunocytochemistry. In order to create these links, formaldehyde undergoes a Mannich reaction in which the formaldehyde forms a methylene bridge between the aminogroup of two amino acids. Crosslinking increases protein stability allowing for more accurate preservation of in vivo conformations which in turn increases binding affinity of fluorochrome conjugated antibodies for fluorescent imaging. Formaldehyde is also a known carcinogen as classified by the National Cancer Institute. Malonic acid, a green, plant-based, water-soluble, and relatively inexpensive polycarboxylic acid has been shown to undergo crosslinking of proteins through an unknown mechanism. To test whether malonic acid can crosslink proteins within cells we fixed SH-5YSY cells with either malonic acid or formaldehyde and then stained with a fluorochrome conjugated antibody for the cytoskeletal protein α-tubulin. The cells were then imaged 72 hours after fixation. We observed a non-significant difference in the fluorescence of immunostained SH-5YSY cells fixed with malonic acid as compared to paraformaldehyde (p-value = 0.2469, ANOVA). In addition, we have created a theoretical mechanism showing malonic acid forming a propyl bridge for crosslinking proteins in a similar mechanism to that of formaldehyde. Here, we show that malonic acid is able to fix cells and retain fluorescence just as well as paraformaldehyde up to 72 hours after fixation and present several possible mechanisms for this chemical process.

Probing and understanding interaction of Eu(Ⅲ)withγ-alumina in presenceof malonic acid

Radionuclide migration in aquatic environment is influenced by its sorption onto colloids/mineral oxides and the presence of organic complexing anions.With a view to understand the sorption of trivalent actinides by mineral oxides in presence of organic acid,in the present study,Eu(Ⅲ),malonic acid(MA)andγ-alumina are considered as representatives of trivalent actinides,low molecular weight natural occurring organic acid and aluminol sites,respectively.The influence of MA on sorption of Eu(Ⅲ)byγ-alumina was elucidated by batch sorption,spectroscopic techniques and surface complexation modeling,for the first time.Attenuated Total Reflection-Fourier Transform Infrared spectroscopic studies of MA sorbed onγ-alumina revealed the presence of two inner-sphere surface complexes.Batch sorption for binary(alumina-Eu(Ⅲ))and ternary(alumina-Eu(Ⅲ)-MA)systems were investigated as a function of p H,Eu(Ⅲ)concentration and sequential addition of Eu(Ⅲ)/MA.The p H edge for Eu(Ⅲ)sorption shifts to higher p H with increasing Eu(Ⅲ)concentration.In ternary systems,Eu(Ⅲ)sorption is significantly enhanced at p H<4.5.Eu(Ⅲ)speciation onγ-alumina is independent of addition sequence of Eu(Ⅲ)/MA.Time resolved fluorescence spectroscopy of Eu(Ⅲ)sorbed onγ-alumina exhibited two surface species,≡XOEu^2+and(≡YO)2 Eu^(+).The enhancement in I 616/I 592 and lifetime for ternary systems,as compared to binary system,at low p H,indicates the participation of Eu-MA complexes in the formation of surface species in ternary systems.The diffuse layer model has been employed to successfully model the experimental sorption profiles of binary and ternary systems,using code FITEQL 4.0,by considering the surface species identified by spectroscopic techniques.

Maleic acid and malonic acid reduced the pathogenicity of Sclerotinia sclerotiorum by inhibiting mycelial growth,sclerotia formation and virulence factors

Sclerotinia sclerotiorum is a necrotrophic plant pathogenic fungus with broad distribution and host range.Bioactive compounds derived from plant extracts have been proven to be effective in controlling S.sclerotiorum.In this study,the mycelial growth of S.sclerotiorum was effectively inhibited by maleic acid,malonic acid,and their combination at a concentration of 2 mg/mL,with respective inhibition rates of 32.5%,9.98%,and 67.6%.The treatment of detached leaves with the two acids resulted in a decrease in lesion diameters.Interestingly,maleic acid and malonic acid decreased the number of sclerotia while simultaneously increasing their weight.The two acids also disrupted the cell structure of sclerotia,leading to sheet-like electron-thin regions.On a molecular level,maleic acid reduced oxalic acid secretion,upregulated the expression of Ss-Odc2 and downregulated CWDE10,Ss-Bi1 and Ss-Ggt1.Differently,malonic acid downregulated CWDE2 and Ss-Odc1.These findings verified that maleic acid and malonic acid could effectively inhibit S.sclerotiorum,providing promising evidence for the development of an environmentally friendly biocontrol agent.

Comparsion of the Effects of Succinate and NADH on Postmortem Metmyoglobin Redcutase Activity and Beef Colour Stability

In two experiments, the effects of succinate and NADH（reduced nicotinamide adenine dinucleotide） on metmyoglobin reductase activity and electron transport chain-linked metmyoglobin reduction were investigated and compared. In experiment 1, metmyoglobin（MetMb）, substrate and inhibitors were incubated with mitochondria. Comparsion of the effects of succinate and NADH on MetMb reduction was investigated. The MetMb percentage in sample treated with 8 mol L-1 succinate decreased by about 69% after 3 h incubation, and the effect was inhibited by the addition of 10 mol L-1 electron transfer chain complex II inhibitor malonic acid; the MetMb percentage in samples treated with 2 mol L-1 NADH decreased by 56% and the effect was inhibited by the addition of 0.02 mol L-1 electron transport chain complex I inhibitor rotenone. These results indicated that electron transport chain played an important role in MetMb reduction. Both complex II and complex I take part in the MetMb reduction in mitochondria through different pathways. NADH-MetMb reduction system was less stable than succinateMetMb system. In experiment 2, the beef longissimus dorsi muscle was blended with different concentrations of succinate or NADH. Enhancing patties with higher concentration of succinate or NADH improved colour stability in vacuum packaged samples（P〈0.05）. These results verified that mitochondria electron transport chain is related to the MetMb reduction in meat system.

Synthesis and Crystal Structure of a Ternary Complex:[Ni(phen)_2(pmal)]·8H_2O

A new ternary complex [Ni（phen）（pmal）]·8H2O （phen = 1,10-phenanthroline, pmal^2- = phenethyl malonic acid） has been synthesized by the reaction of nickel acetate, phen and phenethyl malonic acid. Elemental analysis, IR spectra and X-ray single-crystal diffraction were carried out to determine the composition and crystal structure. Crystal data for this complex： triclinic system, space group PI^-, a = 10.387（5）, b = 13.112（6）, c = 14.229（6） °A, α= 76.176（7）, β = 83.778（8）, γ = 71.770（6）°, C35H42N4O12Ni, Mr= 769.44, Z = 2, F（000） = 808, V = 1786.1°A^3, Dc = 1.431 g/cm^3,μ= 0.612 mm^-1, the final R = 0.0653 and wR = 0.1033 for 9379 （Rint = 0.0244） independent reflections and 4730 observed reflections （I〉 2σ（I））. Structural analysis shows that the coordination geometry of Ni（Ⅱ） is a distorted octahedron. A novel two-dimensional structure is constructed from （H2O）4 and （H2O）12 water clusters, and the complex forms a 3-D network supramolecular structure by hydrogen bonds and π-π stacking of neighboring phens.

Synthesis and Crystal Structure of a Macrocycle[Cu(dadm)(mal)(H_(2)O)]_(2)·2H_(2)O

The reaction of 4,4?-diaminodiphenylmethane (dadm), malonic acid (H2mal) and Cu(NO3)2 in aqueous solution results in a discrete binuclear Cu(II) macrocycle: [Cu(dadm)(mal)- (H2O)]22H2O. It crystallizes in monoclinic, space group P21/c with a = 15.231(3), b = 11.847(2), c = 9.801(2) ? b = 106.75(3)o, V = 1693.5(6) 3, Z = 2, C32H40Cu2N4O12, Mr = 799.76, Dc = 1.568 g/cm3, ?(MoKa) = 0.71073 ? = 1.325 mm-1, F(000) = 828, the final R = 0.0531 and wR = 0.1244 for 3421 observed reflections with I > 2s(I). Each Cu(II) is coordinated by two oxygen atoms from a mal ligand, two nitrogen atoms from two dadm ligands and a water oxygen atom to form a triangle bipyramidal motif. The title compound possesses a distorted macrocycle enclosed by dadm with approximate dimensions of 8.3 ??5.9 ?

Syntheses, characterization, and luminescence of two lanthanide complexes [Ln_2(acetate)_6(H_2O)_4]·4H_2O (Ln=Tb(1), Sm(2))

Two dinuclear compounds [Ln2（acetate）6（H2O）4]-4H2O （Ln=Tb（1）, Sm（2）） were obtained by the hydrothermal reaction of Ln2O3 with malonic acid at 150 ℃. Both compounds were characterized by elemental analyses, infrared spectra, and single crystal X-ray diffraction. The results showed that complexes 1 and 2 were isomorphous and crystallize in triclinic space group P 1. The coordination geometry around Ln（Ⅲ） ions in the complexes 1 and 2 was a distorted tricapped trigonal prism with a nine coordination. In the crystal, the molecular organization was further stabilized by well-defined weak hydrogen bonding interactions between the neutral dinuclear molecular units that led to the formation of a three-dimensional network. The fluorescence properties of the two complexes 1 and 2 in organic solvents were also studied. The results show that the ligand acetate favored energy transfer to the emitting energy level of Tb（Ⅲ） in complex 1. Some factors that influence the fluorescent intensity were also discussed in the article.

Synthesis,Characterization and Thermal Decomposition Behaviour of Tri-aquo Lanthanum(Ⅲ)Malonate Bimalonate

A new complex of malonic acid with lanthanum,La(Hmal)·(mal)·3H_2O,was synthesized and characterized by elemental analysis and IR spectra.The thermal decomposition process and their kinetic parameters n and E_a were studied by means of TG and DTG.All of the intermediate and end products were determined and characterized by the mass loss in TG curve,elemental analysis and IR spectra.

Convenient Solid-phase Synthesis of Benzothiazole Derivatives

Resin-bound cyclic malonic ester l reacted with aryl isothiocynate, then was treated with bromine, followed by cleavage from the resin under perchloric acid to give benzothiazoles 4.

Synthesis, Characterization and Thermophysical Properties of Three Neoteric Solvents-Ionic Liquids Based on Choline Chloride

The authors prepared,characterized and preliminary studied the properties of some neoteric solvents-ionic liquids based on choline chloride,i.e.,three ionic liquids based on the eutectics of choline chloride（2-hydroxyN,N,N-trimethylethanaminium chloride） with,respectively,urea,malonic acid and citric acid.The obtained mixtures were clear and colorless ionic liquids at room temperature.The thermophysical properties,namely,density,viscosity,and electrical conductivity of these mixtures were investigated as a function of temperature within a range of 298-353 K.Correlations for the temperature dependence of the measured properties were generated and discussed in terms of Arrhenius theory.Finally the electrochemical windows of the eutectic liquids were determined.

Organosoluble Aliphatic-Aromatic Poly(ether-amide)s Based on Pyridine Moiety in the Main Chain: Synthesis, Characterization and Thermal Studies

A series organosoluble and heterocyclic poly（ether-amide）s （PEA）s were synthesized from a new diamine containing pyridine moiety and four aliphatic-aromatic dicarboxylic acids by direct polycondensation reactions. Dicarboxilic acids 4a-4d containing ether groups were synthesized in two step reactions. At first, dialdehydes 3a-3d were synthesized from four dibromo alkanes la-ld and 4-hydroxybenzaldehyde 2, then dicarboxilic acids 4a-4d were synthesized from dialdehydes 3a-3d and malonic acid in a solvent free reaction. On the other hand, the new diamine 8 containing pyridine ring was synthesized in two step reactions. The structures of synthesized monomers and polymers were proven by FTIR, NMR spectroscopy and elemental analysis. Also all of the above polymers were fully characterized by inherent viscosity, solubility tests, gel permeation chromatography （GPC）, differential scanning calorimetry （DSC） and thermogravimetric analysis （TGA）. The resulted PEAs have shown good inherent viscosities, solubility and thermal properties.

A Facile Solid Phase Synthesis of 2-Alkylthio-4(1H)-quinolones

The resin-bound cyclic malonic acid ester 2 reacted with aryl isothiocyanate and alkyl halides to afford the key intermediate arylthioaminomethylene cyclic malonic ester resin 3. Subsequently, resin 3 proceeded thermal cyclization giving the 2-alkylthio-4(1H)-quinolones in good yields and excellent purities.