微生物氧化As(III)和Sb(III)的研究进展

砷(Arsenic,As)和锑(Antimony,Sb)属于同族元素,具有相似的化学性质,是公认的有毒类金属(metalloid),广泛存在于自然界中。随着人类的发展,环境中砷和锑的污染日益严重,类金属污染环境的修复已经刻不容缓。现已表明,自然界中的微生物在砷和锑的生物地球化学循环中发挥着重要的作用,尤其是微生物的氧化作用,可以将毒性较强的亚砷酸盐[Arsenite,As(III)]和亚锑酸盐[Antimonite,Sb(III)]氧化为毒性较低的砷酸盐[Arsenate,As(V)]和锑酸盐[Antimonate,Sb(V)],被认为是一种潜在的类金属污染环境修复方法。本文就国内外对As(III)氧化菌和Sb(III)氧化菌的多样性、As(III)和Sb(III)微生物氧化调控机制和应用的研究进展进行总结,旨在为深入了解和探索微生物介导的砷和锑生物地球化学循环及污染环境的微生物修复提供参考。     

β-Diiminatolanthanoid(III) halides revisited

The crystalline compounds [LnCl₂(L)(thf)₂] [Ln = Ce (1), Tb (2), Yb (3)], [NdI₂(L)(thf)₂] (4), [LnCl(L′)₂] [Ln = Tb (5), Yb (6) (a known compound)] and [YbCl(L′′)(μ-Cl)₂Li(OEt₂)₂] (7) have been prepared [L = {N(C₆H₃Prⁱ₂-2,6)C(H)}₂CPh, L′ = {N(SiMe₃)C(Ph)}₂CH, L′′ = {N(SiMe₃)C(C₆H₄Ph-4)}₂CH]. The X-ray molecular structures of 2-7 have been established; in each, the monoanionic ligand L, L′ or L′′ is N,N′-chelating and essentially π-delocalised. Each of 1-7 was prepared from the appropriate LnCl₃, or for 4 [NdI₃(thf)₂], and an equivalent portion of the appropriate alkali metal [Li for 7, Na for 2, 3 and 5, or K for 1, 4 and 6] β-diiminate in thf; the isolation of exclusively 5 and 6 (rather than the L′ analogues of 2 or 3) is noteworthy, as is the structure of 7 which has no precedent in Group 3 or 4f metal β-diiminato chemistry.     

Fe(III)的微生物异化还原

异化Fe(III)还原微生物是厌氧环境中广泛存在的一类主要微生物类群,它们的共同特征是可以利用Fe(III)作为末端电子受体而获能。异化Fe(III)还原微生物具有强大的代谢功能,可还原许多有毒重金属包括一些放射性核素,还可降解利用许多有机污染物,在污染环境的生物修复中具有重要的应用价值。本文对异化Fe(III)还原微生物的分布、分类,代谢功能多样性以及异化Fe(III)还原的意义做了评述,旨在加强相关领域的研究人员对此的了解和重视,通过学科的交叉和合作加快我国在这一领域的研究。     

How can aluminium(III) generate fluorescence?

In a previous paper [F. Launay, V. Alain, E. Destandau, N. Ramos, E. Bardez, P. Baret, J. L. Pierre, New J. Chem. 25 (2001) 1269-1280] [New J. Chem. 25 (2001) 1269], we showed that the hexadentate tripodal ligand O-TRENSOX (O-TR), incorporating three 8-hydroxy-5-sulfoquinoline subunits, was an efficient chelator of Al(III), quantitatively giving the 1:1 chelate in stoichiometric conditions even at the 10(-5) mol L(-1) concentration scale. However, the 1:1 Al:O-TR chelate turned out to be not significantly more fluorescent than the free ligand, whereas fluorescence enhancement by factors of at least 100 occurred either with the 3:1 Al:O-TR chelate, or with the 1:1 complex obtained with n-BUSOX, a ligand similar to one arm of O-TRENSOX. The present paper addresses the unresolved question of the magnitude of the fluorescence enhancement. Time-resolved fluorescence measurements, and additional complexation experiments carried out with the tripod TRENSOXCAMS2 (one 8-HQS and two 5-sulfocatechol subunits) and with n-BUCAMS analogous to one catechol arm of TRENSOXCAMS2, show that stoichiometry between Al(III) and the bound bidentate subunits is the key factor of fluorescence enhancement. The charge density on Al(III), tuned by the number of chelating groups and by their formal charges, influences the photoinduced charge transfer which tends to quench the fluorescence emission of the 8-hydroxyquinoline ligand. Transposition can be done to other bifunctional amphoterous ligands such as morin.     

中国青藓科研究资料(III)

研究了青藓科的7种1变种（Brachythecium planiusculum,Eurhynchium coarctum,E.serricuspis,Rhynchostegium leptomitophyllum,R.longirameum,R.pallenticaule,R.subspeciosum和R.subspeciosum var.filiforme）的模式标本。提出了3个新组合（E urhynchium longirameum,E.filiforme,Bryhnia serricuspis）,     

Polynuclear chromium(III) carboxlylates: Part 2. Chromium(III) acetate — what's in it?

Chromium(III) acetate has been widely used in industry for decades. The commercial material is an ill-defined substance, which represents a large number of compounds having different compositions, physical properties and appearances. Several samples of Cr(III) acetate, from various commercial sources were examined by ion-exchange chromatography. All the samples were found to contain several species such as [Cr₃O(O₂CCH₃)₆(H₂O)₃]⁺ and other positively charged purple complexes. They also contain various amounts of the neutral violet complex [Cr₈(OH)₈(O₂CCH₃)₁₆] (1) which crystallizes upon slow evaporation of its aqueous solution. 1 is a cyclic octanuclear complex with hydroxo and acetate ligands bridging the adjacent Cr(III) ions. The structure of a well-defined Cr(III) acetate, namely, [Cr(H₂O)₆](O₂CCH₃)₃ (2) has been determined crystallographically and its decomposition products were examined by ion-exchange chromatography. Compound 2 decomposes under ambient conditions, releasing acetic acid and water producing neutral and charged polynuclear Cr(III) complexes.     

Synthesis and characterization of tris(β-diketonato)technetium(III) and -(IV) complexes

The preparations and properties of tris(dipivaloylmethanato)technetium(III), tris(trifluoroacetylacetonato)technetium(III), and tris(hexafluoroacetonato)technetium(III) are described. The oxidation of the dipivaloyl derivative to tris(dipivaloyl)technetium(IV) hexafluorophosphate was shown to take place readily. Voltammetric studies and magnetic resonance results on the new complexes are reported. The large shifts observed for the complexes seem to be due to a contact interaction.     

Structure-redox potential relations of some tris(β-dicarbonylato)iron(III) chelates

The polarographic behaviour of a series of tris(β- dicarbonylato)iron(III) chelates is reported. Conventional polarography and voltametric studies in acetonitrile revealed that these complexes undergo a one- electron reduction process at the Hg and carbon fibre electrodes. The influence of substituents within the β-dicarbonylato moiety is discussed in terms of Hammett σ functions. Reduction potentials are related to Racah's interelectronic repulsion parameter B and to the energy of the spin-forbidden transition ⁴T₂g ←⁶A_1g. The polarographic behaviour of binary mixtures indicates that ligand exchange in solution is a fast process and formation of mixed-ligand chelates in solution with predetermined stoichiometry is unlikely.     

Specific cation effect on quenching reactions of excited tris(α,α-diimine)ruthenium(II) and tris(2,2-bipyridine)chromium(III) by tris(oxalato)- and tris(malnato)chromates(III) in aqueous solutions

Specific salt effects were studied on the quenching reaction of excited [Ru(N-N)₃]²⁺ (N-N=2,2^′-bipyridine (bpy), 1,10-phenanthrorine (phen)) and [Cr(bpy)₃]³⁺ by [Cr(ox)₃]³⁻ (ox=oxalate ion) and [Cr(mal)₃]³⁻ (mal=malonate ion) in aqueous solutions as a function of alkali metal ions which were added for adjustment of ionic strength. The value of k_q, quenching rate constants, and k₁, energy transfer rate constant in encounter complex, is changed by the cations as the order of Li⁺ > Na⁺ > K⁺ ≈ Rb⁺ ? Cs⁺, although diffusion rate constants are not changed by the co-existing cations. Among the quenching reactions investigated in this work, a ratio of k₁ values in the aqueous solutions whose ionic strength was adjusted with LiCl and KCl, k₁^LiCl/k₁^KCl, is larger for quenching systems of closely approached donor-acceptor pair than loosely bounded pair. These results indicate that co-existing alkali cation tunes the distance between donor and acceptor in encounter complex where energy transfer occurs.     

Comparison of Au(III) and Ga(III) Ions’ Binding to Calf Thymus DNA: Spectroscopic Characterization and Thermal Analysis

Metals have been studied as potential chemotherapeutic agents for cancer therapies due to their high reactivity toward a wide variety of substances. The characterization of metal ion-binding capacities is essential to understand the possible effects of metals on target biomolecules. In the present study, biochemical effects of Au(III) and Ga(III) ions on calf thymus DNA (ctDNA) were studied comparatively via bioanalytical, spectroscopic, and thermal methods. Briefly, UV-Vis absorbance spectroscopy, fluorescence spectroscopy, circular dichroism (CD) spectroscopy, and Fourier transform infrared (FT-IR) spectroscopy were utilized for spectroscopic characterization, and isothermal titration calorimetry (ITC) measurements were performed for thermal analysis. Our results reveal that both Au(III) and Ga(III) ions are capable of interacting with ctDNA, and Au(III) ions display a more favorable interaction and a higher binding affinity. ITC analyses indicate that the Au(III)-DNA interaction displays a binding affinity (K_a) around 1.43?×?10⁶ M^?1, while a K_a around 1.17?×?10⁵ M^?1 was observed for the Ga(III)-DNA binding. It was suggested that both metal ions are unlikely to change the structural B-conformation while interacting with ctDNA.     

Synthesis,characterization and biodistribution of tris(β-diketonato)technetium(III) complexes

New tris(β-diketonato) complexes of trivalent ⁹⁹Tc/^99mTc with the ligands hexane-2,4-dione, heptane-2,4-dione, heptane-3,5-dione, and octane-3,5-dione were synthesized by reduction of pertechnetate with dithionite in the presence of excess β-diketone. The complexes were purified by HPLC, identified by elemental analysis and FAB mass spectrometry, and characterized by vis./u.v./i.r. spectrophotometry. The hexane-2,4-dionato complex crystallizes in the monoclinic space group P2₁/c, isostructurally with pentane-2,4-dionatotechnetium(III). Biodistribution measurements in mice showed the neutral and lipophilic ^99mTc-diketonato complexes to penetrate the blood-brain barrier. However, increasing lipophilicity decreased the brain uptake except for the heptane-2,4-dionato complex, which displayed the highest uptake of 0.82% injected dose/g.     

Anhydrous and hydrated lanthanide(III) β,δ-triketonates

Complexes of the β,δ-triketones benzoylacetone and diacetylacetone with lanthanide(III) ions are reported. The compounds with the first ligand (formulated Ln(Hbaa)₃) are anhydrous while those with the last one (formulated Ln(Hdaa)₃·H₂O) are hydrated. IR and TGA analyses were carried out to confirm the anhydrous or hydrated character of the complexes. The anhydrous character of the lanthanide complexes with benzoylacetone is discussed in terms of the larger steric requirements in the terminal groups of the ligand with respect to those in the compounds with diacetylacetone.     

Synthese von 1,3,5-Triazinen aus Aminosäure-Derivaten (III)

An extracellular acidic polysaccharide produced by Serratia piscatorum IFO 12527 was found to exhibit a marked antiinflammatory activity. The polysaccharide was purified by fractional precipitation with cetyltrimethylammonium bromide and then by gel filtration on Sepharose 2B to give two homogeneous fractions, PLS N–I and PLS N–II, the former exhibiting the antiinflammatory activity.

PLS N-I was a complex polysaccharide composed of l-rhamnose, d-galactose and d-galacturonic acid in the molar ratio of 2: 1; 1, together with small portions of d-glucosamine, d-galactosamine, protein and fatty acids such as acetic, lauric, myristic, β-hydroxyrnyristic and palmitic acids. Physicochemical and biological properties of PLS N–I and PLS N–II were also described.     

Preparation and characterization of oxovanadium(IV), acetatomanganese(III), chloroiron(III), nickel(II), copper(II), zinc(II) and palladium(II) complexes of 3,3′-(1,2-phenylenediimino)diacrolein

The oxovanadium(IV), acetatomanganese(III), chloroiron(III), nickel(II), copper(II), zinc(II) and palladium(II) of 3,3′-(1,2-phenylenediimino)diacrolein were prepared and investigated by means of mass, electronic, vibrational, NMR and ESR spectroscopy as well as magnetic susceptibility measurements. The acetatomanganese(III) and chloroiron(III) complexes were confirmed to be of high spin type. The absorption bands appearing in the energy range greater than 23 000 cm⁻¹ were attributed to π→π^* transitions within a ligand molecule and charge- transfer transitions from metal to ligand. The metal complexes assume the square-planar configuration type since the ligand-field bands were detected in the 12 700–18 500 cm⁻¹ region. Strong bands appearing at 1601 and 1627 cm⁻¹ were assigned to the CC and CO stretching vibrational modes, respectively, and were shifted to lower frequency upon metal-coordination. A VO stretching band was observed at 982 cm⁻¹ for the oxovanadium(IV) complex and a CO stretching band was observed at 1547 cm⁻¹ for the acetatomanganese(III) complex. Upon complex formation the amine proton signal is found to vanish and the aldehydic methine proton signal in the lowest field is shifted upfield for the nickel(II), zinc(II) and palladium(II) complexes. ¹³C NMR spectra support the coordination structure of the complexes which is revealed by ¹H NMR spectra. As judged by the spin Hamiltonian parameters, the oxovanadium(IV) complex is of a square- planar type with an unpaired electron in the d_xy orbital and the copper(II) complex assumes a distorted square-planar coordination due to the presence of five- and six-membered chelate rings with an unpaired electron in the d_x2−y2 orbital.     

云芝子实体多糖(CVP)化学结构的研究III.

通过化学、IR和UV光谱等方法发现云芝子实体的热水提取物 CVP 是由多糖、核酸和蛋白质等组成的混合物。通过柱层析方法从 CVP 中纯化出一个多糖组份 B-2-3,经完全水解证实组成它的单糖残基主要为Glc。用 HPLC 方法测得其分子量为 5.01×105。通过对甲基化及 1H 和 13C NMR 数据的分析发现 B-2-3 为一个以β-D-1, 4-Glc、β-D-1, 3-Glc 和β-D-1, 6-Glc 残基构成主链,同时在β-D-1, 3, 6-Glc 及β-D-1, 4, 6-Glc 处产生分枝的多糖。     

人分泌粒蛋白III的克隆和表达(英文)

研究了一个新的人分泌蛋白基因_分泌粒蛋白III(secretograninIII,SgIII)。SgIII蛋白序列共有 4 6 8个氨基酸残基 ,N端有一段疏水信号肽 ,序列中含有DSTK重复序列和 7对二元碱性氨基酸 (dibasicsites) ,这些结构特点同其他分泌粒蛋白家族成员相类似。人源SgIII蛋白在小鼠、大鼠和爪蟾中各有一个同源蛋白。基因组分析表明 ,SgIII基因位于人 15号染色体上 ,含有 12个外显子 ,分布在 39kb长的基因组DNA上。Western印迹和免疫细胞化学实验证实 ,SgIII蛋白同其他分泌粒蛋白家族成员一样 ,通过分泌途径被分泌到胞外。SgIII在多种组织中都有表达 ,Northern印迹显示SgIII的mRNA主要有 2 .2kb和 1.9kb两种形式 ,但在脑中还有 4 .5kb和 3.3kb大小的两种特异转录本。     

Spin-trapping studies on the reactions of Cr(III) with hydrogen peroxide in the presence of biological reductants: is Cr(III) non-toxic?

Cr(III), which is thought to be relatively non-toxic, was reduced to Cr(II) ion by biological reductants such as L-cysteine and NADH and Cr(II) thus formed could easily react with hydrogen peroxide (H2O2) to yield very reactive active oxygen species, hydroxyl radical (.OH). The formation of hydroxyl radical was detected by water-soluble spin-traps, alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone (POBN) and 5,5-dimethyl-1-pyrroline N-oxide (DMPO). This result indicates that non-toxic Cr(III) compounds have the possibility of causing dangerous effects to living organism in the presence of biological reductants.