Synthetic, biologically active amphiphilic peptides

Amphiphilic peptides typically consist of a peptide portion that may be 5-25 (or more) amino acids in length. The hydrophobic portion may be a single fatty acid residue, but can also be more elaborate. The main focus of this article lies on the family of synthetic anion binders (SATs) of the general structure (R(1))(2)N-COCH(2)OCH(2)CO-(Aaa)(n)-OR(3). The most-common R(1) group is the octadecyl (C(18)H(37)) group. The most studied peptide sequence in this family is (Gly)(3)-Pro-(Gly)(3), although different sequences (and longer and shorter peptides) have been prepared as well. The C-terminal ester residue providing the most effective anion release from liposomes is heptyl (C(7)H(15)), although many others have been examined. The compound (C(18)H(37))(2)N-COCH(2)OCH(2)CO-(Gly)(3)-Pro-(Gly)(3)-OBn (Bn=benzyl) was found to mediate Cl(-) transport in mouse epithelial cells.     

3-Amidoquinuclidine derivatives: synthesis of compounds and inhibition of butyrylcholinesterase

The synthesis of racemic and enantiomerically pure 3-butanamidoquinuclidines ((+/-)-Bu, (R)-Bu and (S)-Bu), (1-3) and 3-benzamidoquinuclidines ((+/-)-Bz, (R)-Bz, and (S)-Bz), (4-6) is described. The N-quaternary derivatives, N-benzyl-3-butanamidoquinuclidinium bromides ((+/-)-BnlBu, (R)-BnlBu and (S)-BnlBu), (7-9) and N-benzyl-3-benzamidoquinuclidinium bromides ((+/-)-BnlBz, (R)-BnlBz and (S)-BnlBz), (10-12) were subsequently synthesized. The interaction of the four enantiomerically pure quaternary derivatives with horse serum butyrylcholinesterase (BChE) was tested. All tested compounds inhibited the enzyme. The best inhibitior of the enzyme was (S)-BnlBz with a K(i) = 3.7 microM. The inhibitor potency decreases in order (S)-BnlBz > (R)-BnlBz > (R)-BnlBu > (S)-BnlBu.     

Palladium and platinum 3,5-diacetyl-1,2,4-triazol bis(thiosemicarbazones): chemistry, cytotoxic activity and structure-activity relationships

The preparation of platinum(II) complexes derived from 3,5-diacetyl-1,2,4-triazol bis(4-phenylthiosemicarbazone) (H(5)L(1)), 3,5-diacetyl-1,2,4-triazol bis(thiosemicarbazone) (H(7)L(2)), 3,5-diacetyl-1,2,4-triazol bis(4-methylthiosemicarbazone) (H(5)L(3)) and 3,5-diacetyl-1,2,4-triazol bis(4-ethylthiosemicarbazone) (H(5)L(3)) is described. The new complexes [Pt(mu-H(3)L(1))](2), [Pt(mu-H(5)L(2))](2), [Pt(mu-H(3)L(3))](2) and [Pt(mu-H(3)L(4))](2) have been characterized by elemental analyses, fast atom bombardment mass spectrometry (FAB(+)) and spectroscopic studies. The crystal and molecular structure of compounds [Pt(mu-H(3)L(1))](2), parent ligand H(5)L(1) and [Pt(mu-H(3)L(3))](2) have been determined by single crystal X-ray diffraction. The ligands coordinate, in a dideprotonate form to the platinum ions in a new tridentate fashion (NNS) and S-brigding bonding modes. Thus the molecular units of the platinum complexes are stacked as dimers. The testing of the cytotoxic activity of the synthesized compounds together with their palladium analogues against human A2780 and A2780cisR epithelial ovarian carcinoma cells lines suggests that the compounds may be endowed with important antitumor properties since they show IC(50) values in a micromolar range similar to those of cisplatin. The structure and antitumor activity relationships of platinum and palladium complexes are also discussed.     

Enantioselective recognition of ammonium perchlorate salts by optically active monoaza-15-crown-5 ethers

Chiral monoaza-15-crown-5 ethers (1, 2) were prepared from (R)-(-)-2-amino-1-butanol in high yield. The chiral monoaza-15-crown-5 ethers were purified directly as NaClO(4) complexes. Molecular recognition by these chiral monoaza-crown ethers of (R)- and (S)-PhEtHClO(4) and (R)- and (S)-NapEtHClO(4) as characterized by UV-vis spectroscopy. The order of enantiomeric selectivity is (R)- > (S)- PhEtHClO(4) and (S)- > (R)-NapEtHClO(4) for 1. In the case of 2 it was (R)- > (S)-PhEtHClO(4) and (R)- > (S)- NapEtHClO(4). The cavity of macrocycle and steric hindrance of the benzene units appears to play an important role in recognition.     

Distribution and Translocation of 141Ce (III) in Horseradish

BACKGROUND AND AIMS: Rare earth elements (REEs) are used in agriculture and a large amount of them contaminate the environment and enter foods. The distribution and translocation of (141)Ce (III) in horseradish was investigated in order to help understand the biochemical behaviour and toxic mechanism of REEs in plants. METHODS: The distribution and translocation of (141)Ce (III) in horseradish were investigated using autoradiography, liquid scintillation counting (LSC) and electron microscopic autoradiography (EMARG) techniques. The contents of (141)Ce (III) and nutrient elements were analysed using an inductively coupled plasma-atomic emission spectrometer (ICP-AES). RESULTS: The results from autoradiography and LSC indicated that (141)Ce (III) could be absorbed by horseradish and transferred from the leaf to the leaf-stalk and then to the root. The content of (141)Ce (III) in different parts of horseradish was as follows: root > leaf-stalk > leaf. The uptake rates of (141)Ce (III) in horseradish changed with the different organs and time. The content of (141)Ce (III) in developing leaves was greater than that in mature leaves. The results from EMARG indicated that (141)Ce (III) could penetrate through the cell membrane and enter the mesophyll cells, being present in both extra- and intra-cellular deposits. The contents of macronutrients in horseradish were decreased by (141)Ce (III) treatment. CONCLUSIONS: (141)Ce (III) can be absorbed and transferred between organs of horseradish with time, and the distribution was found to be different at different growth stages. (141)Ce (III) can enter the mesophyll cells via apoplast and symplast channels or via plasmodesmata. (141)Ce (III) can disturb the metabolism of macronutrients in horseradish.     

Synthesis of cinnamoyl and hydroxycinnamoyl amino acid conjugates and evaluation of their antioxidant activity.

Fifteen amides of cinnamic, ferulic and sinapic acids with natural and unnatural C-protected amino acids have been synthesized. The amides (E)-N-(feruloyl)-L-tyrosine methyl ester (10), (E)-N-(feruloyl)-L-phenylalanine t-butyl ester (11), (E)-N-(sinapoyl)-L-tyrosine methyl ester (13) and (E)-N-(sinapoyl)-L-phenylalanine t-butyl ester (15) with a free carboxyl group of amino acids have been found in nature. The rest of the compounds are unknown. The hydroxycinnamoyl amino acid conjugates have been studied for their antioxidant activity (AOA) in bulk phase lipid autoxidation. The highest AOA has been found for the compounds 11 and 15, which contain the same phenylalanine moiety.     

花粉抗辐射损伤的动物实验研究

花粉对动物辐射损伤研究的结果为：花粉能提高辐射动物外周血粒细胞,保护骨髓、脾脏、胸腺等组织结构,增加辐射动物血浆超氧化物歧化酶（ＳｕｐｅｒｏｘｉｄｅＤｉｓｍｕｔａｓｅ,ＳＯＤ）的活力,降低脂质过氧化物（ｍａｌｏｎｉｃｄｉａｌｄｅｈｙｄｅ,ＭＤＡ）含量,此外,对辐射动物睾丸的生精作用有一定的保护。这些结果均说明花粉具有多方面的抗辐射损伤效应。     

G protein β1γ2 subunits purification and their interaction with adenylyl cyclase

A preliminary study on the interaction of G protein (guanine triphosphate binding protein) b1g2 subunits and their coupled components in cell signal transduction was conducted in vitro. The insect cell lines, Sf9 (Spodoptera frugiperda) and H5 (Trichoplusia ni) were used to express the recombinant protein Gβ₁γ₂. The cell membrane containing Gβ₁γ₂ was isolated through affinity chromatography column with Ni-NTA agarose by FPLC method, and the highly purified protein was obtained. The adenylyl cyclase 2 (AC2) activity assay showed that the purified Gβ₁γ₂ could significantly stimulate AC₂ activity. The interaction of β₁γ₂ subunits of G protein with the cytoplasmic tail of various mammalian adenylyl cyclases was monitored by BIAcore technology using NTA sensor chip, which relies on the phenomenon of surface plasmon resonance (SPR). The experiments showed the direct binding of Gβ₁γ₂ to the cytoplasmic tail C2 domain of AC2. The specific binding domain of AC2 with Gβ₁γ₂ was the same as AC2 activity domain which was stimulated by Gβ₁γ₂.     

Fourier transform IR and Fourier transform Raman spectroscopy studies of metallothionein-III: amide I band assignments and secondary structural comparison with metallothioneins-I and -II

The secondary structures of porcine brain Cu(4)Zn(3)-metallothionein (MT)-III and Cd(5)Zn(2)MT-I, Cd(5)Zn(2)MT-II, and Zn(7)MT-I from rabbit livers in the solid state are investigated by Fourier transform IR spectroscopy (FTIR) and Fourier transform Raman spectroscopy (FT-Raman). The Cu(4)Zn(3)MT-III contains 26-28% beta-turns and half-turns, 13-14% 3(10)-helices, 47-49% random coils, and 11-12% beta-extended chains. The structural comparison of porcine brain Cu(4)Zn(3)MT-III with rabbit liver Cd(5)Zn(2)MT-I (II) and Zn(7)MT-I shows that the contents of the random coil structure are obviously increased. The results indicate that the insert of an acidic hexapeptide in the alpha domain of Cu(4)Zn(3)MT-III possibly forms an alpha helix. However, because the bands assigned to the alpha-helix and random coil structures are overlapped in the spectra, the content of random coil structures in Cu(4)Zn(3)MT-III is therefore higher than those in Cd(5)Zn(2)MT-I, Cd(5)Zn(2)MT-II, and Zn(7)MT-I.     

Quantification of H/D Isotope Effects on Protein Hydrogen-bonds by h3JNC′ and 1JNC′ Couplings and Peptide Group 15N and 13C′ Chemical Shifts

The effect of hydrogen/deuterium exchange on protein hydrogen bond coupling constants (h3)J(NC') has been investigated in the small globular protein ubiquitin. The couplings across deuterated or protonated hydrogen bonds were measured by a long-range quantitative HA(CACO)NCO experiment. The analysis is combined with a determination of the H(N)/D(N) isotope effect on the amide group (1)J(NC') couplings and the (15)N and (13)C' chemical shifts. On average, H-bond deuteration exchange weakens (h3)J(NC') and strengthens (1)J(NC') couplings. A correlation is found between the size of the (15)N isotope shift, the (15)N chemical shift, and the (h3)J(NC') coupling constants. The data are consistent with a reduction of donor-acceptor overlap as expected from the classical Ubbelohde effect and the common understanding that H(N)/D(N) exchange leads to a shortening of the N-hydron bond length.     

五角枫种群表型多样性

为揭示五角枫种群的表型分化程度、变异模式及地理变异规律,以山西19个种群为研究对象,采用巢式方差分析、相关分析、聚类分析等方法从形态学角度对五角枫种群的叶片、果实、种子等23个表型性状进行了系统分析。结果表明:(1)五角枫23个表型性状中除果柄长、着生痕、种子长/宽以外,其余20个表型性状在种群间和种群内均存在显著和极显著差异。(2)19个种群的平均变异系数为18.07。叶片、果实、种子的平均表型变异系数依次为:果实19.78%叶片18.77%种子10.25%。(3)五角枫种群间表型分化系数(VST)均值为48.82%,种群内变异(51.18%)与种群间变异(48.82%)基本相当。叶片、果实、种子表型分化系数的平均值为:叶片58.08%果实41.24%种子25.87%。(4)五角枫叶片、果实和种子的信息多样性指数(H)为:叶片6.1079果实5.9118种子5.2855;多样性指数平均值(D)分别为:果实0.9967叶片0.9961种子0.9948。(5)主成分分析结果显示:五角枫种群表型多样性基本来源为:叶片贡献率果实贡献率种子贡献率。(6)五角枫表型变异呈现出以经度和纬度变异并存的趋势,少数表型性状与经度和纬度呈现显著或极显著相关。(7)利用欧氏距离对五角枫种群进行UPGMA聚类分析,将五角枫19个种群划分为两大类群。五角枫种群具有较高的表型多样性,种群间和种群内均存在丰富的表型变异,与其遗传特点和分布生境等密切相关,研究结果为今后五角枫种质资源的保护和利用奠定了基础。     

鸣禽控制发声核团和脑干听觉核团及神经通路的综合研究

采用辣根过氧化物酶顺、逆行标记方法对鸣禽鸟蜡嘴雀控制发声的神经核团、脑干听觉核团及神经通路,从外周至中枢逐级进行了追踪研究。结果表明：１．控制发声的神经核团及通路,前脑古纹状体腹内侧粗核是大脑控制发声的重要核团之一,它发出枕中脑后束经端脑前联合呈双侧支配延脑中间核,中间核又发出舌下神经经气管鸣管分支支配鸣肌,中间核同时也接受中脑背内侧核的支配,２．脑干听觉中枢及通路,中脑背外侧核是脑干较高级听觉中枢、初级中枢耳蜗核由角核和前庭外侧核组成,ＮＡ发出以对侧为主的纤维经外侧丘系可直接传入中脑背外侧核形成脑干听觉直接通路。     

Study on the interactions between anti-HIV-1 active compounds with trans-activation response RNA by affinity capillary electrophoresis

The study on the interactions between two anti-human immunodeficiency virus type 1 (anti-HIV-1) active compounds with trans-activation response (TAR) RNA by affinity capillary electrophoresis (ACE) with UV absorbance detection is presented. The results showed that the novel active molecules could interact with TAR RNA and inhibit the reproduce process of HIV-1. The binding constants were estimated by the change of migration time of the analytes through the change of concentrations of TAR RNA in the buffer solution. The yielded binding constants of 8.87 x 10(3)M(-1) for active compound C(3) and 8.42 x 10(3)M(-1) for MC(3) at 20.0 degrees C, 0.626 x 10(3)M(-1) and 0.644 x 10(3)M(-1) at 37.0 degrees C, respectively. The thermodynamic parameters Delta H and DeltaS were obtained and shown that both hydrophobic and electrostatic interaction played roles in the binding processes. The results showed that the presented method was an easy and simple method to evaluate the interaction of small molecules with some bioactive materials.     

Catalytic properties of the PepQ prolidase from Escherichia coli

The PepQ prolidase from Escherichia coli catalyzes the hydrolysis of dipeptide substrates with a proline residue at the C-terminus. The pepQ gene has been cloned, overexpressed, and the enzyme purified to homogeneity. The k(cat) and k(cat)/K(m) values for the hydrolysis of Met-Pro are 109 s(-1) and 8.4 x 10(5)M(-1)s(-1), respectively. The enzyme also catalyzes the stereoselective hydrolysis of organophosphate triesters and organophosphonate diesters. A series of 16 organophosphate triesters with a p-nitrophenyl leaving group were assessed as substrates for PepQ. The S(P)-enantiomer of methyl phenyl p-nitrophenyl phosphate was hydrolyzed with a k(cat) of 36 min(-1) and a k(cat)/K(m) of 710 M(-1)s(-1). The corresponding R(P)-enantiomer was hydrolyzed more slowly with a k(cat) of 0.4 min(-1) and a k(cat)/K(m) of 11 M(-1)s(-1). The PepQ prolidase can be utilized for the kinetic resolution of racemic phosphate esters. The PepQ prolidase was shown to hydrolyze the p-nitrophenyl analogs of the nerve agents GB (sarin), GD (soman), GF, and VX.     

Preparation, structures and electrochemical property of phosphine substituted diiron azadithiolates relevant to the active site of Fe-only hydrogenases

Mono- and di-phosphine diiron azadithiolate complexes [{(mu-SCH(2))(2)N(4-NO(2)C(6)H(4))}Fe(2)(CO)(5)(PMe(3))] (2), [{(mu-SCH(2))(2)N(4-NO(2)C(6)H(4))}{Fe(CO)(2)L}(2)] (3, L=PMe(3); 4, PMe(2)Ph) and the mu-hydride diiron complex [3(FeHFe)](+)[PF(6)](-) were prepared as biomimetic models of the active site of Fe-only hydrogenases. The complexes 2-4 and [3(FeHFe)](+)[PF(6)](-) were characterized by IR, (31)P, (1)H and (13)C NMR spectra and their molecular structures were determined by single crystal X-ray analyses. The PMe(3) ligand in complex 2 lies on the basal position. The PMe(3)-disubstituted complex 3 exists as two configuration isomers, transoid basal/basal and apical/basal, in the crystalline state, while two PMe(2)Ph ligands of 4 are in an apical/basal orientation. The variable temperature (31)P NMR spectra of 2 and 3 were made to have an insight into the existence of the possible conformation isomers of 2 and 3 in solution. The [3(FeHFe)](+) cation possesses the sole transoid ba/ba geometry as other reported mu-hydride diiron analogues. The electrocatalytic property of {(mu-SCH(2))(2)NC(6)H(5)}[Fe(CO)(2)PMe(3)](2) (5) was studied for proton reduction in the presence of HOAc.     

Determination of tetracycline, chlortetracycline and oxytetracycline by flow injection with inhibitory chemiluminescence detection using copper(II) as a probe ion.

This paper reports an indirect flow-injection (FI) method for the determination of the tetracycline drugs (TCs), tetracycline (TC), chlortetracycline (CTC) and oxytetracycline (OTC), using copper(II) as a probe ion. The method was based on the inhibition caused by these TCs to the copper(II)-catalysed chemiluminescence (CL) reaction between luminol and H(2)O(2). The CL reaction was induced on-line and injection of the sample produced negative peaks as a result of the copper(II) complexation or displacement by the analytes. The height of the peaks was proportional to the drug concentration in the sample. The choice of the catalyst ion, the concentration of luminol, H(2)O(2) and copper(II) are discussed. The linear range was 3.6 x 10(-8)-1.0 x 10(-5), 1.1 x 10(-7)-1.0 x 10(-5) and 1.9 x 10(-7)-1.0 x 10(-5) mol/L for TC, CTC and OTC, respectively. The detection limit was 5.0 x 10(-9) mol/L for TC, 1.0 x 10(-8) mol/L for CTC and 2.0 x 10(-8) mol/L for OTC (3sigma), respectively. The method was applied to the determination of TCs in pharmaceutical preparations and human urine with recoveries in the range 95-105%.     

Catalytic behavior of Pseudomonas cepacia lipase in w/o microemulsions

The activity of purified Pseudomonas cepacia lipase has been investigated in esterification reactions of various aliphatic alcohols with natural fatty acids. The reactions were carried out in microemulsions formed in isooctane by bis-(2-ethylhexyl)sulfosuccinate sodium salt (AOT). Kinetic studies showed that the reaction follows a ping-pong bi-bi mechanism with inhibition by both substrates. The apparent kinetic parameters of the reaction were found to be K(m octanol) = 310 mM, K(m lauric acid) = 78 mM, and V(max) = 250 mumol min(-1) mg(-1). The same system was used for the synthesis of mono- and diglycerides from glycerol and lauric acid, which was successful at very low w(o) values. The catalytic behavior of P. cepacia lipase was also studied in esterification reactions performed in a nonionic microemulsion system formulated by tetraethyleneglycoldodecylether (C(12)E(4)). The optimum activity was found at about w(o) = 8. The apparent values of V(max app) and K(m app) for octanol were calculated and found to be 100 mumol min(-1) mg(-1) and 76 mM, respectively. (c) 1995 John Wiley & Sons, Inc.     

Positive coupling of atypical adenosine A3 receptors on human eosinophils to adenylyl cyclase

Adenosine A(3) receptors are reported to couple negatively to adenylyl cyclase (AC) but their mediation of anti-inflammatory effects in human eosinophils prompted us to investigate their coupling to AC. The A(3)-selective agonists IB-MECA and Cl-IB-MECA evoked a concentration-dependent generation of cAMP (EC(50), 3.2 and 1.8 microM, respectively) and were more potent than the A(2A) agonist CGS 21680 (EC(50)=15.4 microM) and adenosine (EC(50)=19.2 microM). The cAMP response was additive to that produced by forskolin (10 microM). The effect of IB-MECA was insensitive to A(1) and A(2A) receptor antagonists, but was antagonized by the A(3)-selective antagonist MRS 1220 (0.1-2.5 microM) in a competitive manner. The estimated K(B) of 190 nM was, however, atypical. The cyclo-oxygenase inhibitor, indomethacin, had no effect on the cAMP response. A general inverse relationship between cAMP generation and inhibition of degranulation was seen. We conclude that in human eosinophils, an atypical form of A(3) receptors positively coupled to AC may exist. The resulting cAMP generation may underlie the anti-inflammatory actions of A(3) agonists in eosinophils.     

组建油桐尺蠖核型多角体病毒基因组物理图谱的计算机方法

 本文报道了一种双酶混合切割后用计算机对结果进行分析、比较及组建出物理图谱的方法。用Bam HⅠ、BglⅡ等限制性内切酶进行单酶双酶切割,计算出油桐尺蠖核型多角体病毒基因组DNA的分子量为120.23Kb,BamHⅠ切割DNA后产生10条带;BglⅡ切割后产生7条带。经计算机分析后打印出前者在物理图谱中的顺序为A(GE)C(HI)B(DFJ),后者在物理图谱中的顺序为AGC(EF)BD。在本文中还提出了组建图谱的计算机程序思想,并讨论了此法的可靠性。     

Variability in essential-oil composition of Piper marginatum sensu lato

This paper contains data on the chemical composition of the essential oils of 22 leaf samples of Piper marginatum Jacq. collected in different areas and ecosystems of the brazilian Amazon, as well as an overview of the available literature. The species presents a large synonymy based on their different leaf characteristics and distinct scents where some of them smell like anise or very close compounds. By GC, GC/MS, and cluster analysis, we identified seven chemotypes for the leaf oils. The main components found in chemotype I were safrole (1) and 3,4-(methylenedioxy)propiophenone (2). The chemotype II was dominated by 3,4-(methylenedioxy)propiophenone (2) and p-mentha-1(7),8-diene (10). The major compounds identified in chemotype III were 3,4-(methylenedioxy)propiophenone (2), myristicin (3), (E)-beta-ocimene (11), and gamma-terpinene (12). In the chemotype IV, the principal constituents were beta-caryophyllene (13), alpha-copaene (14), and 3,4-(methylenedioxy)propiophenone (2). The chemotype V was dominated by (E)-isoosmorhizole (6), (E)-anethole (8), and isoosmorhizole (7). The main compounds found in the chemotype VI were 2-methoxy-4,5-(methylenedioxy)propiophenone (4), methoxy-4,5-(methylenedioxy)propiophenone isomer 5, and (E)-isoosmorhizole (6). The major constituents in chemotype VII were beta-caryophyllene (13), bicyclogermacrene (15), and (E)-asarone (9).