Measurement of aromatisation by a urine technique suitable for the evaluation of aromatase inhibitors in vivo.

By modification of a recently developed method for separation of radio-labelled urinary oestrogens we were able to separate oestrogen metabolites and measure their isotope ratios in urine following injections of [3H]delta 4-androstenedione and [14C]oestrone. This method provides a useful tool for studying in vivo aromatisation of delta 4-androstenedione into oestrone in breast cancer patients before and during treatment with aromatase inhibitors.     

In vitro metabolism of a mixture of [4-C]pregnenolone and [17α-H]pregnenolone by polycystic ovary: Pathways of testosterone biosynthesis

When minced polycystic ovarian tissue was incubated with a mixture of [4-¹⁴C]-pregnenolone and [17α-³H]pregnenolone² and added cofactors for 25, 40 and 60 min, the following metabolites were isolated and characterized: progesterone, 17-hydroxyprogesterone, 17-hydroxypregnenolone, dehydroepiandrosterone, 4-androstenedione, and testosterone; unmetabolized substrates were also recovered. There were increased amounts of progesterone, 17-hydroxyprogesterone, dehydroepiandrosterone, and 4-androstenedione formed as the incubation time increased.     

Synthesis of novel selenium containing sulfa drugs and their antibacterial activities

Synthesis of 3-[4-(N-substituted sulfamoyl)phenyl]-3,4-dihydro-4-oxo-7,9-dimethylpyri-do[3′,2′:4,5]selenolo[3,2-d]pyrimidines,7-[4-(N-substituted sulfamoyl)phenyl]-7,8-dihydro-8-oxo-3,4-diphenylpyrimido[4′,5′:4,5]selenolo [2,3-c]pyridazines and 1-[4-(N-substituted sulfamoyl)phenyl]-1,11-dihydro 11-oxo-4-methylpyrimido[4′,5′:4,5]selenolo[2,3-b]quinolines is reported. 4-Amino-N-pyrimidine-2-ylbenzene sulfonamide (a), 4-amino-N-(2,6-dimethylpyrimidin-4-yl)benzene sulfonamide (b), N-[(4-aminophenyl)sulfonyl] acetamide (c) with N-ethoxymethyleneamino of selenolo pyridine, selenolo pyridazine and selenolo quinoline derivatives respectively were obtained starting from 1-amino-N ⁴-substituted sulfanilamides. Spectroscopic data (IR, ¹H NMR, ¹³C NMR and Mass spectral) confirmed the structure of the newly synthesized compounds. Substituted pyrimidines, pyridazines and quinolines were screened for antibacterial activity against gram-positive and gram-negative bacteria. Selenolo derivative of N-[(4-aminophenyl)sulfonyl] acetamide (substitutent of sulfacetamide c) showed strong bactericidal effect against all the tested organisms. Selenolo[3,2-d]pyrimidin (substitutent a) showed a good bactericidal effect against Serratia marcescens, Staphylococcus aureus and Escherichia coli. Compounds selenolo[2,3-c]pyridazine (substitutent b), selenolo[2,3-b]quinoline(substitutents c)) exhibited a moderate bactericidal effect against Serratia marcescens. None of the synthesized seleno pyridazines has a considerable antimicrobial activity against the tested organisms. The minimum inhibitory concentration (MIC) of the most active compound-3-[4-(N-acetyl sulfamoyl)phenyl]-3,4-dihydro-4-oxo-7,9-dimethylpyrido[3′,2′:4,5]selenolo [3,2-d]pyrimidine was 10 mg ml⁻¹.     

In vitro steroidogenesis of the gonads of the protogynous Pacific wrasse, Haliochoeres trimaculatus

Testicular and ovarian fragments of the protogynous Pacific wrasse Haliochoeres trimaculatus were incubated in vitro with [³H]pregnenolone ([³H]P₅), [³H]17‐hydroxyprogesterone ([³H]17OHP₄), non‐radioactive (nr) 17β‐oestradiol (nrE₂) or nrP₅ to identify the major gonadal steroidogenic pathways and steroid products in females and in the two male variants of this species, the terminal phase (TP) and initial phase (IP) males. Both testis and ovarian tissues exhibited 7 hydroxylase activity resulting in the formation of 7α‐hydroxypregnenolone (7OHP₅) from [³H]P₅, and many HPLC peaks were identified as products of testicular (c. 29) and ovarian (c. 23) steroidogenesis, and only c. 50% of these metabolites co‐eluted with authentic reference standards; only very small amounts of conjugated steroid were synthesized from any of the precursors. [³H]P₅ was converted by testis mainly to 7αOHP₅, and two unknown steroids, whereas [³H]17OHP₄ metabolism gave rise to [³H]17,20β‐dihydroxy‐4‐pregnen‐3‐one (DHP), 11‐ketotestosterone (11KT), and two unknown steroids. For ovarian tissues, [³H]17OHP₄ and [³H]P₅ were metabolized to form E₂, oestrone (E₁), androstenedione (A₄), 20α‐ and 20β‐dihydroprogesterone (20αDHP and 20βDHP), 7αOHP₅ (from [³H]P₅) and a major unknown. The HPLC steroid profiles for testis incubations for IP and TP males were similar, however, the steroidogenic response of the testis of TP males to human chorionic gonadotrophin, in vitro (determined by hormone assay), was significantly higher than that of IP males.     

EFFICIENT METHODS FOR THE SYNTHESIS OF [2-15N]GUANOSINE AND 2′-DEOXY[2-15N]GUANOSINE DERIVATIVES

The nucleophilic addition–elimination reaction of 2′,3′,5′-tri-O-acetyl-2-fluoro-O ⁶-[2-(4-nitrophenyl)ethyl]inosine (8) with [¹⁵N]benzylamine in the presence of triethylamine afforded the N ²-benzyl[2-¹⁵N]guanosine derivative (13) in a high yield, which was further converted into the N ²-benzoyl[2-¹⁵N] guanosine derivative by treatment with ruthenium trichloride and tetrabutyl-ammonium periodate. A similar sequence of reactions of 2′,3′,5′-tri-O-acetyl-2-fluoro-O ⁶-[2-(methylthio)ethyl]inosine (9) and the 6-chloro-2-fluoro-9-(β-D-ribofuranosyl)-9H-purine derivative (11), which were respectively prepared from guanosine, with potassium [¹⁵N]phthalimide afforded the N ²-phthaloyl [2-¹⁵N]guanosine derivative (15; 62%) and 9-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)-6-chloro-2-[¹⁵N]phthalimido-9H-purine (17; 64%), respectively. Compounds 15 and 17 were then efficiently converted into 2′,3′,5′-tri-O-acetyl[2-¹⁵N]guanosine. The corresponding 2′-deoxy derivatives (16 and 18) were also synthesized through similar procedures.     

Modelling Metal Complexes of Calixarene Esters and Phosphine Oxides Using Molecular Mechanics

This paper focuses on the molecular modelling of a number of calixarene ester and phosphine oxide metal ion complexes. Monte Carlo conformational searches, in conjunction with the Merck Molecular Force Field, were carried out using Spartan SGI Version 5.0.1. running on Silicon Graphics O2 workstations. In the case of the calix[4]arene tetraesters, the optimised models strongly suggest that the selectivity of these ligands is strongly related to the eight-fold nature of the coordination with the Na⁺ ion, while coordination with the Li⁺ ion, for example, is merely three-fold. This feature of eight-fold coordination is also observed in the models of the complexes formed by the calix[4]arene tetraphosphine oxides with calcium. However, whereas the eight-fold coordination is unique to the model of the TPOL:Ca²⁺ complex among the ions modelled, this mode of coordination occurs for TPOS with sodium and potassium, in addition to calcium. This concurs with the observation that calcium selectivity is obtained with ion selective electrodes based on TPOL but not TPOS. Though the cavity in the calix[5]arenes PPOL and PPOLx and the calix[6]arene HPOL, in their uncomplexed form, are much larger than that of the corresponding calix[4]arenes, the pattern of selectivity is the same – the ligands are selective for calcium. The models of the complexes of these larger calixarenes, such as PPOL:Ca²⁺, strongly suggest that the reason for this similarity is that four of the available phosphine oxide groups complex with the calcium ion, and the others are forced away from the cavity region for steric reasons. The resulting eight-fold coordination, is therefore, similar to that of the calix[4]arenes studied.Electronic Supplementary Material available.     

Honokiol and Magnolol Increase the Number of [3H]Muscimol Binding Sites Three-Fold in Rat Forebrain Membranes In Vitro Using a Filtration Assay,by Allosterically Increasing the Affinities of Low-Affinity Sites

1. The bark of the root and stem of various Magnolia species has been used in Traditional Chinese Medicine to treat a variety of disorders including anxiety and nervous disturbances. The biphenolic compounds honokiol (H) and magnolol (M), the main components of the Chinese medicinal plant Magnolia officinalis, interact with GABA_A receptors in rat brain in vitro. We compared the effects of H and M on [³H]muscimol (MUS) and [³H]flunitrazepam (FNM) binding using EDTA/water dialyzed rat brain membranes in a buffer containing 150 mM NaCl plus 5 mM Tris-HCl, pH 7.5 as well as [³⁵S]t-butylbicyclophosphorothionate (TBPS) in 200 mM KBr plus 5 mM Tris-HCl, pH 7.5. H and M had similar enhancing effects on [³H]MUS as well as on [³H]FNM binding to rat brain membrane preparations, but H was 2.5 to 5.2 times more potent than M. 2. [ ³ H]FNM binding. GABA alone almost doubled [³H]FNM binding with EC₅₀ = 450 nM and 200 nM using forebrain and cerebellar membranes, respectively. In the presence of 5 M H or M the EC₅₀ values for GABA were decreased to 79 and 89 nM, respectively, using forebrain, and 39 and 78 nM, using cerebellar membranes. H and M potently enhanced the potentiating effect of 200 nM GABA on [³H]FNM binding with EC₅₀ values of 0.61 M and 1.6 M using forebrain membranes, with maximal enhancements of 33 and 47%, respectively. Using cerebellar membranes, the corresponding values were 0.25 and 1.1 M, and 22 and 34%. 3. [ ³ H]MUS binding. H and M increased [³H]MUS binding to whole forebrain membranes about 3-fold with EC₅₀ values of 6.0 and 15 M. Using cerebellar membranes, H and M increased [³H]MUS binding ~68% with EC₅₀ values of 2.3 and 12 M, respectively. Scatchard analysis revealed that the enhancements of [³H]MUS binding were due primarily to increases in the number of binding sites (B_max values) with no effect on the high affinity binding constants (K_d values). The enhancing effect of H and M were not additive. 4. [ ³⁵ S]TBPS binding. H and M displaced [³⁵S]TBPS binding from sites on whole rat forebrain membranes with IC₅₀ values of 7.8 and 6.0 M, respectively. Using cerebellar membranes, the corresponding IC₅₀ values were 5.3 and 4.8 M. These inhibitory effects were reversed by the potent GABA_A receptor blocker R5135 (10 nM), suggesting that H and M allosterically increase the affinity of GABA_A receptors for GABA and MUS by binding to sites in GABA_A receptor complexes. 5. Two monophenols, the anesthetic propofol (2,6-diisopropylphenol, P) and the anti-inflammatory diflunisal (2,4-difluoro-4-hydroxy-3-biphenyl carboxylic acid, D) also enhanced [³H]MUS binding, decreased the EC₅₀ values for GABA in enhancing [³H]FNM binding and potentiated the enhancing effect of 200 nM GABA on [³H]FNM binding, although enhancements of [³H]MUS binding for these monophenols were smaller than those for H and M, using forebrain and cerebellar membranes. The enhancing effect of P and D on [³H]MUS binding were almost completely additive. 2,2-biphenol was inactive on [³H]MUS and [³H]FNM binding. These, and other preliminary experiments, suggest that appropriate ortho (C2) and para (C4) substitution increases the GABA-potentiating activity of phenols. 6. The potentiation of GABAergic neurotransmission by H and M is probably involved in their previously reported anxiolytic and central depressant effects.     

Corticoid formation by the monkey fetal adrenal: Evaluation of 17-, 21- and 11-hydroxylase activities

There is indirect evidence that cortisol synthesis in the fetal rhesus monkey adrenal gland is limited at Day 135 of gestation but increases thereafter. This study was conducted to ascertain whether a reduced synthetic capacity is caused by a deficiency in 17-, 21- or 11-hydroxylase activity. For the sake of comparison 11- and 21-hydroxylases were also estimated in adult adrenals. 11-, 21-Hydroxylases were measured in the entire adrenal by the oxidation of NADPH by mitochondria and microsomes, respectively. 17-Hydroxylase was evaluated in outer and inner regions of the fetal gland by the formation of [³H]17-hydroxyprogesterone, -11-deoxycortisol, -cortisol and -androstenedione from [³H]progesterone. The maximum velocity of both the 11- and 21-hydroxylase was similar in fetal and adult glands indicating that corticoid formation in the fetus is not constrained by levels of these enzymes.[³H]Progesterone was extensively metabolized to -17-hydroxyprogesterone, -androstenedione, -11-deoxycortisol and -cortisol by homogenates from both regions of the fetal adrenal. The ratio of [³H]-cortisol to [³H]11-deoxycortisol was consistently higher in incubations of the inner glandular area. Together, these findings indicate that 17-hydroxylase is also active at Day 135 and that the 11-hydroxylase may be more concentrated in the fetal cortex. These data suggest in addition that the restriction in cortisol formation occurs at a step prior to the metabolism of progesterone to cortisol.     

New development in the tritium labelling of peptides and proteins using solid catalytic isotopic exchange with spillover-tritium

Summary.  The mechanism of the reaction of high temperature solid state catalytic isotope exchange (HSCIE) of hydrogen in peptides with spillover-tritium at 140–180°C was analyzed. This reaction was used for preparing [³H]enkephalins such as [³H]DALG with specific activity of 138 Ci/mmol and [³H]LENK with specific activity of 120 Ci/mmol at 180°C. The analogues of [³H]ACTG_4–10 with specific activity of 80 Ci/mmol, [³H]zervamicin IIB with specific activity of 70 Ci/mmol and [³H]conotoxin G1 with specific activity 35 Ci/mmol were produced. The obtained preparations completely retained their biological activity. [³H]Peptide analysis using ³H NMR spectroscopy on a Varian UNITY-600 spectrometer at 640 MHz was carried out. The reaction ability of amino fragments in HSCIE was shown to depend both of their structures and on the availability and the mobility of the peptide chain. The reaction of HSCIE with the β-galactosidase from Termoanaerobacter ethanolicus was studied. The selected HSCIE conditions allow to prepare [³H] β-galactosidase with specific activity of 1440 Ci/mmol and completely retained its the enzymatic activity. Received November 30, 2001 Accepted January 31, 2002 Published online December 18, 2002 Acknowledgments The work was supported by the Russian Foundation for Basic Research, grant 01-04-48519a. Authors' address: Dr. Yurii A. Zolotarev, Institute of Molecular Genetics, Russian Academy of Sciences, pl. Kurchatova 2, 123182, Moscow, Russia, Fax: +7 (095) 196-0221, E-mail: zolya@img.ras.ru Abbreviations: HSCIE, the reaction of high temperature solid state catalytic isotope exchange; HS, hydrogen spillover; ³H NMR, tritium nuclear magnetic spectroscopy; CtxG1, conotoxin G1; AchR, acetylcholine receptor; HF, Hartree-Fock ab initio quantum-chemical calculation method     

An Efficient Method for the Synthesis of [4–15N]Cytidine, 2′-Deoxy[4–15N]Cytidine, [6–15N]adenosine,and 2′-Deoxy [6–15N]adenosine Derivatives

Abstract

Nucleophilic substitution reactions of 4-azolyl-1 β-P-D-ribofuranosylpyrimidin-2(1H)-one and 6-azolyl-9-β-D-ribofuranosyl-9H-purine derivatives, which were converted from uridine and inosine, with [¹⁵N]phthalimide in the presence of triethylamine or DBU gave N ⁴-phthaloyl[4-¹⁵N]cytidine and N ⁶-phthaloyl[6-¹⁵N]- adenosine derivatives, respectively, in high yields. Similar reactions of those azolyl derivatives with succinimide afforded N ⁴-succinylcytidine and N ⁶-succinyladenosine derivatives in high yields. The corresponding 2′-deoxyribonucleosides were also synthesized efficiently through the same procedure.

     

Synthesis of 2′-Deoxy[5′-13C]Ribonucleotides and HMQC-Noesy NMR Study of the Dickerson's Dodecamer with 13C-Labeling at the 5′ Positions

Abstract

In addition to the synthesis of 2′-deoxy[5′-¹³C]ribonucleosides (6) via the D-[5-¹³C]ribose derivative (4), the construction of the corresponding dodecanucleotide with the Dickerson's sequence and its HMQC-NOESY NMR analysis are described.     

Synthesis,Conformational Analysis,and Biological Activity of a Rigid Carbocyclic Analogue of 2′-Deoxy Aristeromycin Built on a Bicyclo[3.1.0]hexane Template

Abstract

A new chiral synthesis of the pseudosugar synthon (1R,2S,4R,5S)-1-[(benzyloxy)methyl]-2-tert-butyloxy-4-hydroxybicyclo[3.1.0]hexane (12) is reported. This compound was used as a template for the construction of carbocyclic nucleoside 4, a conformationally rigid analogue of 2′-deoxyaristeromycin. The X-ray structure and ¹H NMR analysis confirmed the exclusive North [2′-exo (₂E)] conformation of 4 which is vastly different from that of other non-rigid carbocyclic nucleosides. Compound 4 showed good in vitro antiviral activity against human cytomegalovirus and EBV with minimal cytotoxicity.

     

Organometallic indolo[3,2-c]quinolines versus indolo[3,2-d]benzazepines: synthesis, structural and spectroscopic characterization, and biological efficacy

The synthesis of ruthenium(II) and osmium(II) arene complexes with the closely related indolo[3,2-c]quinolines N-(11H-indolo[3,2-c]quinolin-6-yl)-ethane-1,2-diamine (L ¹ ) and N′-(11H-indolo[3,2-c]quinolin-6-yl)-N,N-dimethylethane-1,2-diamine (L ² ) and indolo[3,2-d]benzazepines N-(7,12-dihydroindolo-[3,2-d][1]benzazepin-6-yl)-ethane-1,2-diamine (L ³ ) and N′-(7,12-dihydroindolo-[3,2-d][1]benzazepin-6-yl)-N,N-dimethylethane-1,2-diamine (L ⁴ ) of the general formulas [(η⁶-p-cymene)M^II(L ¹ )Cl]Cl, where M is Ru (4) and Os (6), [(η⁶-p-cymene)M^II(L ² )Cl]Cl, where M is Ru (5) and Os (7), [(η⁶-p-cymene)M^II(L ³ )Cl]Cl, where M is Ru (8) and Os (10), and [(η⁶-p-cymene)M^II(L ⁴ )Cl]Cl, where M is Ru (9) and Os (11), is reported. The compounds have been comprehensively characterized by elemental analysis, electrospray ionization mass spectrometry, spectroscopy (IR, UV–vis, and NMR), and X-ray crystallography (L ¹ ·HCl, 4·H₂O, 5, and 9·2.5H₂O). Structure–activity relationships with regard to cytotoxicity and cell cycle effects in human cancer cells as well as cyclin-dependent kinase (cdk) inhibition and DNA intercalation in cell-free settings have been established. The metal-free indolo[3,2-c]quinolines inhibit cancer cell growth in vitro, with IC₅₀ values in the high nanomolar range, whereas those of the related indolo[3,2-d]benzazepines are in the low micromolar range. In cell-free experiments, these classes of compounds inhibit the activity of cdk2/cyclin E, but the much higher cytotoxicity and stronger cell cycle effects of indoloquinolines L ¹ and 7 are not paralleled by a substantially higher kinase inhibition compared with indolobenzazepines L ⁴ and 11, arguing for additional targets and molecular effects, such as intercalation into DNA.     

Synthesis,characterization, and antimicrobial evaluation of some new hydrazinecarbothioamide, 1,2,4-triazole and 1,3,4-thiadiazole derivatives

In this work, we reported the synthesis and evaluation of antibacterial and antifungal activities of three new compound series obtained from 6-(phenyl/4-chlorophenyl)imidazo[2,1-b]thiazole-3-acetic acid hydrazide: 2-{[6-(phenyl/4-chlorophenyl)imidazo[2,1-b]thiazol-3-yl]acetyl}-N-alkyl/arylhydrazinecarbothioamides (2a–d), 4-alkyl/aryl-2,4-dihydro-5-{[6-(phenyl/4-chlorophenyl)imidazo[2,1-b]thiazol-3-yl]methyl}-3H-1,2,4-triazole-3-thiones (3a–n), and 2-alkyl/arylamino-5-{[6-(phenyl/4-chlorophenyl)imidazo[2,1-b]thiazol-3-yl]methyl}-1,3,4-thiadiazoles (4a–g). The newly synthesized compounds were characterized by IR, ¹H NMR, ¹³C NMR (APT), mass and elemental analysis. Their antibacterial and antifungal activities were evaluated against Staphylococcus aureus ATCC 29213, Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922, Candida albicans ATCC 10231, C. parapsilosis ATCC 22019, C. krusei ATCC 6258, Trichophyton mentagrophytes var. erinacei NCPF 375, Microsporum gypseum NCPF 580, and T. tonsurans NCPF 245. 3c, 3f, 3m, 3n, and 4e showed the highest antibacterial activity. Particularly 3c, 3f, 3g, 3k, 3n, 4a, 4e, and 4g showed the highest antifungal activity against tested fungi.     

Radiolabelled Pyrimidine Nucleosides to Monitor the Expression of HSV-1 Thymidine Kinase in Gene Therapy

Abstract

Selective radiolabelling and imaging of transduced HSV tk expressing cells was studied using [¹²³I]IVFRU, [¹²⁵I]FIRU and [¹²⁵I]FIAU. Although all three radionucleosides accumulated in the KBALB-STK transduced murine tumour line in vitro and in vivo, [¹²⁵I]FIRU provided optimal performance in terms of selectivity for HSV tk expressing cells and % of injected dose accumulating in the tumor.     

人工湿地反应性填料开发及其脱氮除磷性能研究

【目的】人工湿地填料作为反硝化电子供体可以高效且稳定地脱氮除磷,但是填料的选用方式和作用机理尚不明确。【方法】本文以磁黄铁矿、菱铁矿和农业废弃物(木屑等)为人工湿地填料,研究了其对人工湿地反硝化脱氮除磷的效果。【结果】结果显示,质量比1:1的矿石组合和木屑以3:1的质量比作为混合填料,驯化8个周期后NO₃^--N和PO₄^3--P的平均去除率达到88.6%和88.9%。扫描电子显微镜(scanning electron microscopy,SEM)、X射线光电子能谱(X-ray photoelectron spectroscopy,XPS)、X射线衍射仪(X-ray diffraction,XRD)和群落分析结果表明,微生物能有效利用矿石及其次生产物和木屑进行高效和持久的脱氮除磷,脱氮除磷功能菌硫杆菌(Thiobacillus)、罗姆布茨菌(Romboutsia)和溶杆菌(Lysobacter)得到了富集。【结论】本研究为人工湿地实际应用中新型填料的选择提供理论依据与指导意义。     

Synthesis and biological evaluation of tricarbonyl Re(I) and Tc(I) complexes anchored by poly(azolyl)borates: application on the design of radiopharmaceuticals for the targeting of 5-HT<Subscript>1A</Subscript> receptors

The building blocks fac-[^99mTc{κ³-HB(tim^Me)₃}(CO)₃] and fac-[^99mTc{κ³-R(μ-H)B(tim^Me)₂}(CO)₃] [R is H (4a), Ph (5a); tim^Me is 2-mercapto-1-methylimidazolyl] were obtained almost quantitatively by reacting fac-[^99mTc(CO)₃(H₂O)₃]⁺ with the corresponding scorpionate. These compounds cross the intact blood–brain barrier in mice, with significant retention in the case of 4a and 5a. Using 4a as the lead structure, we have synthesized the functionalized complexes fac-[M{κ³-H(μ-H)B(tim^Bu-pip)₂}(CO)₃] [M is Re (8), ^99mTc (8a); tim^Bu-pip is methyl[4-((2-methoxyphenyl)-1-piperazinyl)butyl](2-mercapto-1-methylimidazol-5-yl)methanamide] and fac-[M{κ ³-H(μ-H)B(tim^Me)(tim^Bu-pip)}(CO)₃] [M is Re (9), ^99mTc (9a)] and evaluated their potential as radioactive probes for the targeting of brain 5-HT_1A serotonergic receptors. The Re complexes exhibit excellent affinity [IC₅₀=0.172 ± 0.003 nM (8); IC₅₀=0.65 ± 0.01 nM (9)] for the 5-HT_1A receptor. The radioactive congeners (^99mTc) have shown an initial brain uptake of 1.38 ± 0.46%ID g⁻¹ (8a) and 0.43 ± 0.12%ID g⁻¹ (9a), but suffer from a relatively fast washout.     

8-AZA-7-DEAZAADENINE AND 7-DEAZAGUANINE: SYNTHESIS AND PROPERTIES OF NUCLEOSIDES AND OLIGONUCLEOTIDES WITH NUCLEOBASES LINKED AT POSITION-8

The 8-aza-7-deazaadenine (pyrazolo[3,4-d]pyrimidin-4-amine) N⁸-(2′-deoxy-ribonucleoside) (2) and the 7-deazaguanine (pyrrolo[3,4-d]pyrimidine-2-amin-(3H)-4-one) C⁸-(2′-deoxyribonucleoside) (4) were synthesized and incorporated in oligonucleotides employing phosphoramidite chemistry. Oligonucleotides carrying compound 2 are able to form base pairs with the four canonical DNA constituents without significant structural discrimination. The nucleoside 4 was obtained from the corresponding ribonucleoside by deoxygenation. Oligonucleotides containing compound 4 showed similar base pairing properties as those with 2′-deoxyisoguanosine.     

Synthesis of 2′-Deuterio Tubercidin and Adenosine and the Corresponding Arabino Analogs

Abstract

The 2′-deuterio arabino analogs of tubercidin and adenosine have been prepared by Swern oxidation of the 3′,5′-TPDS derivatives of tubercidin and adenosine and reduction with NaBD_4. Subsequent inversion of stereochemistry at C-2′ yielded [2′-²H]tubercidin and [2′-²H]adenosine with 98% deuterium incorporation.     

基于Ti4+-IMAC富集的分枝菌酸小杆菌深度覆盖磷酸化蛋白质组研究

【目的】本研究以分枝菌酸小杆菌(Mycolicibacterium smegmatis)为研究对象,探索适于原核微生物理想的磷酸化富集方法。【方法】我们比较了二氧化钛(TiO₂)、Fe³⁺-NTA和Ti⁴⁺螯合在磷酸酯修饰的固相微球(Ti⁴⁺-IMAC) 3种不同富集方法磷酸化肽段的富集效率,并用不同分辨率的质谱仪评估富集稳定性。【结果】Ti⁴⁺-IMAC富集效率最高,磷酸化位点数是TiO₂或Fe³⁺-NTA方法的7倍以上;TiO₂和Fe³⁺-NTA方法富集到的磷酸化位点数相差不大,与已报道的用TiO₂方法富集的磷酸化位点数目接近。Ti⁴⁺-IMAC富集结果稳定性很好,高分辨率Lumos质谱仪鉴定到的磷酸化位点数是Velos的2.6倍。【结论】本研究较高效地实现了分枝菌酸小杆菌磷酸化事件的鉴定,共鉴定到2 280个磷酸化蛋白、10 880个磷酸化肽段及4 433个可信磷酸化位点,有望用于其他微生物的磷酸化蛋白质组学研究。