An efficient synthesis of the plant growth hormone 1-triacontanol

Summary A high yield synthesis of 1-triacontanol was based on the cheap and easily available starting materials 1-octadecanol and 1,12-dodecanediol. The first one was converted to octadecanal using a phase transfer system, whereas the second one after phase transfer bromination and reaction with triphenylphosphine provided 1-hydroxy-12-triphenylphosphonium bromide.Wittig reaction of these two synthons and subsequent hydrogenation furnished the desired product.

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Eine effiziente Synthese des Pflanzenwachstumshormons 1-Triacontanol

Zusammenfassung Eine Synthese von 1-Triacontanol, basierend auf den einfach zugänglichen Edukten 1-Oktadecanol und 1,12-Dodecandiol, die gute Ausbeuten ergibt, wird beschrieben. Ersteres Edukt wurde mit Hilfe eines Phasentransfersystems zu Oktadecanal umgesetzt. Letzteres gab nach Phasentransfer-Bromierung und Umsatz mit Triphenylphosphin 1-Hydroxy-12-triphenylphosphoniumbromid.Wittig-Reaktion dieser beiden Synthone und anschließende Hydrierung lieferte das erwünschte Produkt.

     

Effect of iron and humic acid on photodegradation of some pesticides adsorbed on clay surfaces

Photochemistry studies can be helpful in assessing the environmental fate of chemicals. For this reason, the photodegradation kinetic studies of the two pesticides orthophenylphenol (OPP) and monuron, largely used in agriculture, were carried out in solid phase. The fungicide OPP and the herbicide monuron were irradiated on the clay fractions (montmorillonite and modified clays) using a suntest simulator. The phototransformation of the parent compound was followed by HPLC technique. The photodegradation process appears to follow the first order reaction. Kinetic parameters were determined and the experimental results show that the photodegradation of these substrates was enhanced in presence of K-montmorillonite, in comparison with Fe(III) exchanged montmorillonite and montmorillonite complexed with humic acid complexes. This study has shown that the iron and humic acid adsorbed on clay surfaces did not increase the degradation rate.     

Using a new solvation model for thermodynamic study on the interaction of nickel with human growth hormone

Thermodynamics of the interaction between Ni²⁺ and human growth hormone (hGH) were determined at 27 °C in Nail solution by isothermal titration calorimetry. A new method to predict protein penetration and the effect of metal ions on the stability of proteins is introduced. The new solvation model was used to reproduce the enthalpies of Ni²⁺-hGH interaction over the whole range of Ni²⁺ concentrations. The solvation parameters recovered from the new equation, attributed to the structural change of hGH and its biological activity.     

Preparative alkaline urea gradient PAGE: application to purification of extraordinarily-stable disulfide-linked homodimer of human growth hormone

The 40-60 pituitary human growth hormone (hGH) isoforms are so similar in their physico-chemical properties (charge, size, hydrophobicity) that the limited resolutions of chromatographic separation methodologies have not permitted most of them to be isolated. However, application of high-resolution preparative alkaline urea gradient PAGE has facilitated isolation of a disulfide-linked mercaptoethanol-resistant (MER) 45 kDa hGH dimer. Human pituitary extracts were separated by Sephadex G-100 chromatography under alkaline conditions. Pooled fractions containing MER-45 kDa hGH, as determined by SDS-PAGE, were then separated by Sephadex G-100 chromatography under acidic conditions followed by diethylaminoethyl (DEAE) anion-exchange chromatography. Pooled DEAE fractions containing MER-45 kDa hGH and other hGH isoforms were then separated by preparative electrophoresis in an alkaline polyacrylamide gradient (5-20%) slab gel containing 8 M urea into five distinct protein zones. One electroeluted zone contained pure MER-45 kDa hGH. The dimeric hGH isoform was immunoreactive at low concentrations (effective dose to produce 50% response (ED(50)) +/- S.E. = 58 +/- 5.00 pM) in a hGH radioimmunoassay, similar to that of standard monomeric hGH (ED(50) +/- S.E. = 22.93 +/- 3.90 pM), indicating that is was conformationally intact. Alkaline urea gradient PAGE is a valuable tool for preparative separation of structurally similar proteins such as isoforms of the hGH family.     

Binding properties and structural changes of human growth hormone upon interaction with cobalt ion

Binding properties and structural changes of human growth hormone (hGH) due to the interaction by cobalt ion (Co²⁺) were done at 27°C in NaCl solution, 50 mM, using different techniques of UV-Vis spectroscopy, circular dichroism (CD), isothermal titration calorimetry (ITC) and differential scanning calorimetry (DSC) techniques. There is a set of three identical and non-interacting binding sites for cobalt ions. The intrinsic association equilibrium constant and the molar enthalpy of binding obtained by ITC are 0.80 mM⁻¹ and −16.70 kJ mol⁻¹, respectively. The intrinsic association equilibrium constant obtained by a standard isothermal titration UV-Vis spectrophotometry method is also 0.79 mM⁻¹, which is in good agreement with the value obtained from ITC. The Gibbs free energy and entropy changes due to the binding of cobalt ion on hGH are −16.67 kJ mol⁻¹ and −0.1 J K⁻¹ mol⁻¹, respectively. Energetic domains analysis by DSC shows that phase transition of hGH in the presence of cobalt occurs at one main transition. Deconvolution of the main transition provides two sub-transitions with different values of the melting point and enthalpy of unfolding (33°C and 164 kJ mol⁻¹ for the first and 49°C and 177 kJ mol⁻¹ for the second, respectively). Interaction of cobalt ions with hGH prevents aggregation by an affect on the hydrophobicity of the protein macromolecule and provide useful information about its structure due to becoming reversible of protein thermal denaturation.     

Electrochemical detection of herbicides and plant growth regulators at membrane glassy carbon electrodes

Membrane glassy carbon electrodes modified with cation-exchangers (Eastman AQ-29D, laponite, or polystyrene sulfonate) entrapped between the membrane and the carbon surface were used to study the electrochemical behavior of herbicides and plant growth regulators from the quaternary ammonium family. Cations are shown to incorporate in the entrapped solutions containing negatively charged cation-exchangers, because of favorable electrostatic interactions. In the case of nonelectroactive cations, collection of mepiquat, chlormequat and difenzoquat from the bulk solution is assessed from the competition in ion-exchange equilibrium between one of the above-mentioned cations and the electroactive diquat cation. An attractive property results from the use of spinach ferredoxin as cation-exchanger inside the membrane electrode. Promotion of ferredoxin is shown to be evidenced as a result of the collection of nonelectroactive cations from the bulk solution. Prospects of such modified membrane electrodes in the environmental field are discussed.     

梯度洗脱测定植物源调节剂中内源激素方法探讨

建立了梯度洗脱高效液相色谱法同时测定内源激素赤霉素(GA3)、吲哚乙酸(3-IAA)、脱落酸(ABA)、细胞分裂素(6-BA)和α-萘乙酸(α-NAA)等5种植物内源激素的方法,采用Hypersil ODS C18柱和紫外检测器,以甲醇、乙腈和0.6%的乙酸为流动相梯度洗脱,分别在各组分的保留时间段设置其最佳检测波长,在12 min内可将上述5种内源激素的各组分分离完全,峰形良好,该方法的回收率可达到90%～96%,线性相关系数(r)大于0.998,检出限在0.02～0.3 μg/g之间.还探讨了各组分的最佳检测条件和梯度洗脱存在的问题及解决方法.     

Separation of proteins with a molecular mass difference of 2 kDa utilizing preparative double-inverted gradient polyacrylamide gel electrophoresis under nonreducing conditions: application to the isolation of 24 kDa human growth hormone

A method for separating proteins with a molecular mass difference of 2 kDa using SDS-PAGE under nonreducing conditions is presented. A sample mixture containing several human growth hormone (hGH) isoforms was initially separated on a weak anion-exchange column. Fractions rich in 24 kDa hGH as determined by analytical SDS-PAGE were pooled and further separated by cation-exchange chromatography. The fractions pooled from the cation-exchange chromatography contained two hGH isoforms with a 2 kDa molecular mass difference according to SDS-PAGE analysis, 22 and 24 kDa hGH. The 22 and 24 kDa hGH were separated using continuous-elution preparative double-inverted gradient PAGE (PDG-PAGE) under nonreducing conditions. The preparative electrophoresis gel was composed of three stacked tubular polyacrylamide matrices, a 4% stacking gel, a 13-18% linear gradient gel, and a 15-10% linear inverted gradient gel. Fractions containing purified 24 kDa hGH were pooled and Western blot analysis displayed immunoreactivity to antihGH antibodies. PDG-PAGE provides researchers with an electrophoretic technique to preparatively purify proteins under nonreducing conditions with molecular mass differences of 2 kDa.     

Size prediction of recombinant human growth hormone nanoparticles produced by supercritical fluid precipitation

Solution-enhanced dispersion by supercritical fluids (SEDS) was applied to produce nano-sized recombinant human growth hormone (hGH) particles. Ethanol was used to help the supercritical carbon dioxide to extract water from the aqueous protein solution. Various sizes of hGH nanoparticles were successfully prepared with a narrow particle size distribution from aqueous ethanol solution without using any additive. The theoretical particle sizes were deduced from the calculated droplet sizes based on a modified Jasuja’s equation. The calculated mean particle sizes and the experimentally obtained ones were compared and the results showed an excellent correlation coefficient (R ²) of 0.995. Figure Distribution of hGH Nano-particles     

淇河鲫生长激素(growth hormone)全长cDNA的克隆与序列分析

用RT-PCR法和3′、5′RACE(Rapid amplification of cDNAends)法从淇河鲫脑垂体RNA克隆出生长激素(Growth hormone,GH)cDNA.此cDNA全长1191 nt(含Poly(A)14 nt),其5′端非编码区长55 nt、阅读框(Open readingframe,OAF)长633 nt,3′端非编码区长503 nt.其推导的GH由210个氨基酸组成,其中氮端前22个氨基酸为信号肽部分.氨基酸序列比较表明:淇河鲫与同目的鲫鱼、鲤鱼、团头鲂和斑马鱼的同源性分别为98.6%,96.2%,91.5%和88.6%;与不同目鱼的胡子鲇和鳗鲡的同源性分别为74.6%和49.5%;与哺乳类的家鼠和人等的同源性低于40%.     

Application of a simple calorimetric data analysis on the binding study of calcium ions by human growth hormone

A simple graphical linear method was introduced for isothermal titration calorimetric data analysis in the protein-ligand interaction. The number of binding sites, the dissociation binding constant and the molar enthalpy of binding site can be obtained by using this new isothermal titration calorimetric data analysis method. The method was applied to the study of the interaction of human growth hormone (hGH) with divalent calcium ion at 27°C in NaCl solution, 50 mM. hGH has a set of three identical and independent binding sites for Ca ²⁺ . The intrinsic dissociation equilibrium constant and the molar enthalpy of binding are 52 μMand -17.4, respectively. Results obtained by this new calorimetric data analysis are in good agreement with results obtained using our previous method.     

Ternary complexes of some phenoxyacetic acid herbicides and pyridines with metal ions of biological interest

Ternary complexes of Co(II), Ni(II) and Cu(II) with pyridine (Py) or 2-methyl pyridine (2-MePy) (primary ligand) and some phenoxyacetic acid herbicides, such as phenoxyacetic acid (PAA), 2-chlorophenoxyacetic acid (2-CPA), 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) (secondary ligands) have been studied in solution using a potentiometricpH-titration technique in order to test a complexation hypothesis of plant growth regulating activities of these herbicides. From stability constant data, the species distribution have been computed and it was found that the percentage of ternary complex (MAL) is about 60% of the totalM ²⁺ present at highpH indicating greater stability of these ternary complexes. TheMA ⁺ species (M ²⁺-Py andM ²⁺-2-MePy) have shown discriminating behaviour towards the next incoming secondary ligand containing O as donor atoms. Since the stabilities of biologically active (2-CPA, 2,4-D and2,4,5-T) and inactive (PAA) phenoxyacetic acid herbicides in binary (ML ₂) and ternary (MAL) metal complexes were found approximately of the same magnitude, chelation may not thus be the probable mode of action of these plant growth regulators.

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Ternäre Komplexe einiger Phenoxyessigsäure-Herbizide mit Pyridin und Metallionen von biologischer Bedeutung

Zusammenfassung Ternäre Komplexe von Co(II), Ni(II) und Cu(II) mit Pyridin (Py) oder 2-Methylpyridin (2-Me Py) als Primärliganden und einigen Herbiziden vom Phenoxyessigsäure-Typ [Phenoxyessigsäure (PAA), 2-Chlor-PAA (2-CPA), 2,4-Dichlor-PAA (2,4-D) und 2,4,5-Trichlor-PAA (2,4,5-T)] als Sekundärliganden wurden im Hinblick auf eine Komplexierungshypothese der pflanzenwuchssteuernden Wirkung dieser Herbizide mittels potentiometrischerpH-Titration untersucht. Aus den Stabilitätskonstanten wurden die Anteile der einzelnen Spezien in Lösung berechnet. Dabei wurden 60% an ternärem Komplex (MAL) — bezogen auf die totaleM ^2–-Menge — bei hohenpH-Werten festgestellt und damit die größere Stabilität dieser Komplexe gezeigt. DieMA ⁺-Spezies (M ²⁺-Py undM ²⁺-MePy) zeigte ein unterschiedliches Verhalten gegenüber dem nächsten chelierenden Liganden mit O als Donor. Da die Stabilitäten der biologisch aktiven (2-CPA, 2,4-D und2,4,5,-T) und inaktiven (PAA) Liganden in binären (ML ₂) und ternären (MAL) Metallkomplexen in der gleichen Größenordnung liegen, scheint die Komplexierung bei der Regulierung des Pflanzenwuchses bei diesen Herbiziden kein entscheidender Faktor zu sein.

     

Quantification of human growth hormone by amino acid composition analysis using isotope dilution liquid-chromatography tandem mass spectrometry

We describe an accurate method for protein quantification based on conventional acid hydrolysis and an isotope dilution-HPLC-mass spectrometry (ID-HPLC-MS) method. Sample purity was confirmed using capillary zone electrophoresis, HPLC and MS. The analyte protein, human growth hormone (hGH), was effectively hydrolyzed by incubation with 8 M hydrochloric acid at 130 °C for 48 h, where at least 1 μM of hGH was treated to avoid possible degradation of released amino acids during hydrolysis. Using a reversed-phase column, the analytes (isoleucine, phenylalanine, proline and valine) were separated within 5 min using an isocratic eluent comprising 10% acetonitrile containing 0.1% trifluoroacetic acid. The detection limit (signal to noise ratio of 3) of amino acids was 5.5-6.2 fmol per injection. The quantification precision (RSD) of amino acids for intra- and inter-day assays was less than 0.98% and 0.39%, respectively. Comparison with other biochemical and instrumental methods revealed substantially higher accuracy and reproducibility of the ID-HPLC-MS/MS method as expected. The optimized hydrolysis and analytical conditions in our study were suitable for accurate quantification of hGH.     

O-乙基-O-(取代γ-丁内酯基-α-次甲基N-烷基(或N,N-二烷基)硫代磷酰胺酯类化合物的合成

硫代磷酰胺酯类化合物在农药领域中有广泛的应用,为了寻找高效低毒的新药剂,人们改变了各种取代基团,其中研究数量最多的为有机磷杂环酯类和取代苯基酯类,但将内酯环结构引入这类化合物中的工作还未见文献报道,出于一些本身含有内酯环结构的天然产物杀菌剂存在于植物体内使植物具有抗病性,因此,本文参考一般内酯和硫代磷酰胺酯的合     

促红细胞生成素和人生长激素兴奋剂检测方法的研究进展

在2008年世界反兴奋剂组织颁布的兴奋剂目录中,S2项肽类激素及相关品种均属于内源性生物大分子物质,如何区分所检测物质属于外界摄入还是机体分泌是此项检测的重点与难点。本文针对其中应用最为普遍、研究较为深入的促红细胞生成素(EPO)和人生长激素(hGH)的检测,从间接血液指标检测、直接检测途径等方面进行了分类评述,侧重于从理化分析方法、免疫分析方法角度阐述识别及区分重组蛋白与内源性蛋白的新途径。     

Cholinesterase sensors based on screen-printed electrodes for detection of organophosphorus and carbamic pesticides

Cholinesterase sensors based on screen-printed electrodes modified with polyaniline, 7,7,8,8-tetracyanoquinodimethane (TCNQ), and Prussian blue have been developed and tested for detection of anticholinesterase pesticides in aqueous solution and in spiked grape juice. The influence of enzyme source and detection mode on biosensor performance was explored. It was shown that modification of the electrodes results in significant improvement of their analytical characteristics for pesticide determination. Thus, the slopes of the calibration curves obtained with modified electrodes were increased twofold and the detection limits of the pesticides were reduced by factors of 1.6 to 1.8 in comparison with the use of unmodified transducers. The biosensors developed make it possible to detect down to 2×10^–8 mol L^–1 chloropyrifos-methyl, 5×10^–8 mol L^–1 coumaphos, and 8×10^–9 mol L^–1 carbofuran in aqueous solution and grape juice. The optimal conditions for grape juice pretreatment were determined to diminish interference from the sample matrix.Abbreviations ChE Cholinesterase - TCNQ 7,7,8,8-Tetracyanoquinodimethane - ChO Choline oxidase - AChE Acetylcholinesterase - BChE Butyrylcholinesterase - BSA Bovine serum albumin - 2-PAM 2-Pyridine aldoxime methiodide     

Remediation of metalliferous soils through the heavy metal resistant plant growth promoting bacteria: Paradigms and prospects

Various industrial, agricultural and military operations have released huge amounts of toxic heavy metals into the environment with deleterious effects on soils, water and air. Under metal stress, soil microorganisms including plant growth promoting bacteria (PGPB) have developed many strategies to evade the toxicity generated by the various heavy metals. Such metal resistant PGPB, when used as bioinoculant or biofertilizers, significantly improved the growth of plants in heavy metal contaminated/stressed soils. Application of bacteria possessing metal detoxifying traits along with plant-beneficial properties is a cost effective and environmental friendly metal bioremediation approach. This review highlights the different mechanisms of metal resistance and plant growth promotion of metal resistant PGPB as well as the recent development in exploitation of these bacteria in bioremediation of heavy metals in different agroecosystems.     

Development of a metabonomic approach based on LC-ESI-HRMS measurements for profiling of metabolic changes induced by recombinant equine growth hormone in horse urine

Despite the worldwide existing regulation banning the use of the recombinant equine growth hormone (reGH) as growth promoter, it is suspected to be used in horseracing to improve performances. Various analytical methods previously developed to screen for its misuse have encountered some limitations in terms of detection timeframes, in particular during the first days following reGH administration. A novel strategy involving the characterization of global metabolomic fingerprints in urine samples of non-treated and reGH-treated horses by liquid chromatography–electrospray–high-resolution mass spectrometry (LC-ESI-HRMS) is described and assessed in this paper in order to develop a new screening tool for growth hormone abuse in horseracing. The strategy involves a limited sample preparation of the urine samples and the use of appropriate software for data processing and analysis. As preliminary work, reproducibility of both sample preparation and mass spectrometry (MS) measurements was evaluated in order to demonstrate the reliability of the method. Application of the developed protocol on two horses demonstrated the suitability of the developed strategy and preliminary results showed significant modifications of the metabolome after treatment with reGH.       

Development of a new stir bar sorptive extraction coating and its application for the determination of six pesticides in sugarcane juice

In this article, a novel polydimethylsiloxane/activated carbon (PDMS‐ACB) material is proposed as a new polymeric phase for stir bar sorptive extraction (SBSE). The PDMS‐ACB stir bar, assembled using a simple Teflon^®/glass capillary mold, demonstrated remarkable stability and resistance to organic solvents for more than 150 extractions. The SBSE bar has a diameter of 2.36 mm and a length of 2.2 cm and is prepared to contain 92 μL of polymer coating. This new PDMS‐ACB bar was evaluated for its ability to determine the quantity of pesticides in sugarcane juice samples by performing liquid desorption (LD) in 200 μL of ethyl acetate and analyzing the solvent through gas chromatography coupled with mass spectrometry (GC‐MS). A fractional factorial design was used to evaluate the main parameters involved in the extraction procedure. Then, a central composite design with a star configuration was used to optimize the significant extraction parameters. The method used demonstrated a limit of quantification (LOQ) of 0.5–40 μg/L, depending on the analyte detected; the amount of recovery varied from 0.18 to 49.50%, and the intraday precision ranged from 0.072 to 8.40%. The method was used in the analysis of real sugarcane juice samples commercially available in local markets.     

The application of levulinic acid and 5-nitro-2-furylmethylene diacetate in the total synthesis of some novel biologically active (5-nitro-2-furyl)azomethines

Summary The syntheses andin vitro antibacterial and antifungal evaluation of certain (5-nitro-2-furyl)azomethines with different heterocyclic nuclei are described.

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Die Anwendung von Lävulinsäure und 5-Nitro-2-furylmethylendiacetat in der Totalsynthese einiger neuer biologisch aktiver (5-Nitro-2-furyl)azomethine

Zusammenfassung Es wird die Synthese und diein-vitro-antibakterielle und antifungale Wirksamkeit für bestimmte (5-Nitro-2-furyl)azomethine mit verschiedenen heterocyclischen Kernen beschrieben.