耐性真菌HA吸附铅、锌的影响因素及吸附机理研

【目的】从铅锌矿区分离筛选出耐铅锌性菌株,并研究其吸附铅、锌的影响因素及吸附机理,为重金属污染微生物修复提供参考。【方法】以从铅锌矿区筛选出的耐铅锌真菌HA作为试验菌株,考察影响其对铅、锌去除能力的主要因素(初始浓度、pH、接种量),同时通过等温吸附模型、动力学分析及红外光谱分析探讨其相关的吸附机理。【结果】经鉴定,从矿区筛选的对Pb2+、Zn2+有较强耐性的菌株HA为米曲霉(Aspergillus oryzae);在初始铅、锌浓度的实验范围内(100-800mg/L),HA对铅、锌离子的去除率随着其初始浓度增加而减小,25h后HA的生长进入平稳期,且对铅、锌离子的去除率趋于稳定。当铅、锌初始浓度为100mg/L、pH为5.0时,HA对铅、锌离子的去除率均达到最高,分别为97.8%、54.1%;当HA接种量为1mL时,其对铅、锌去除率的增长率达到最大。HA对铅、锌的吸附过程满足Langmuir吸附模型,其吸附以单层吸附为主。在动态吸附过程中,HA对Pb2+、Zn2+离子吸附性能与准二级动力学吸附方程的拟合程度更高,且对Pb2+的吸附效果明显高于Zn2+。红外光谱分析表明,HA细胞中羟基、烷基、酰胺基、羰基、磷酸基等参与了Pb2+、Zn2+的吸附过程。【结论】HA是一株对铅、锌有较强吸附能力的真菌,其吸附铅、锌影响因素及吸附机理研究结果将为重金属污染微生物修复提供指导。     

白腐真菌吸附铅的研究

含重金属废水的传统处理方法有化学沉淀法、离子交换法、吸附法、电解法和膜分离法等,它们虽然也能达到一定的净化效果,但因过程繁琐并易造成二次污染而不够理想,尤其是金属离子浓度较低时,往往操作费用和原材料成本相对过高。近年来采用生物吸附法去除废水中的重金属...     

丛枝菌根真菌菌丝体吸附重金属的潜力及特征

应用玻璃珠分室培养系统获得丛枝菌根真菌材料,研究了离体真菌菌丝体对pH缓冲体系中Zn、Cd和Mn等金属离子的吸附特征。试验结果表明,真菌菌丝体对各金属离子吸附能力差异显著,对Cd最强,Zn次之,Mn最弱。试验条件下,菌体可分别吸附相当于自身干物重1.6%的Mn、2.8%的Zn和13.3%的Cdo吸附于菌丝体的Cd2+绝大部分可以被Ca2+交换吸附。另外研究了宿主植物根系对Cd的吸附作用,证实菌根真菌侵染改变了根系的吸附特性,相对于非菌根根系,菌根的CEC较高,对Cd的吸附能力较强。试验结果为重金属污染条件下丛枝菌根强化根系的屏障作用提供了直接证据。     

铅锌胁迫下轮叶黑藻的吸附水平及生理响应

为探讨铅锌胁迫下轮叶黑藻(Hydrilla verticillate)的吸附水平及生理响应,分别设置不同Pb²⁺(浓度梯度为0、0.01、0.05、0.10和0.20 mg/L)、Zn²⁺(浓度梯度为0、0.05、1.00、2.00和4.00 mg/L)浓度单一和复合胁迫轮叶黑藻28d,测定其对铅锌的吸附量,叶绿素a、叶绿素b、丙二醛(MDA)和总抗氧化能力(T-AOC)含量,以及超氧化物歧化酶(SOD)和过氧化物酶(POD)的活性变化。结果显示:高浓度(≥1.00 mg/L)的Zn²⁺可促进轮叶黑藻对Pb²⁺的吸收,对Zn²⁺的吸附主要受Zn²⁺处理浓度的影响;低浓度Pb²⁺和Zn²⁺可以促进叶绿素的合成,高浓度(浓度≥1.00 mg/L)胁迫则抑制叶绿素的合成;受到胁迫时其抗氧化系统会迅速作出反应,但一定浓度的Pb²⁺与Zn²⁺在单一和复合胁迫下,抗氧化系统受限,说...     

不同程度铅锌污染区丛枝菌根真菌和深色有隔内生真菌侵染特征

对陕西凤县铅硐山铅锌矿区4个不同程度铅锌污染样地植物根系的丛枝菌根真菌(AMF)和深色有隔内生真菌(DSE)进行了资源和分布调查。结果表明:(1)无铅锌污染的矿山上调查的15种植物中除黄连木没有检测到AMF侵染、栓皮栎和酸模不能被DSE侵染外,其他植物均能与AMF和DSE共生,但平均侵染率较低,仅分别为32.3%和25.9%;铅锌轻度污染的尾矿荒地和铅中度污染、锌重度污染的尾矿坝植物根系内AMF和DSE侵染率明显提高,AMF的平均侵染率分别为53.3%和68.3%,DSE的平均侵染率分别为38.6%和54.2%;铅锌重度污染的废弃冶炼厂样地植物AMF侵染率明显下降,平均只有17.6%,而DSE的侵染没有受重金属污染的抑制,仍达到60.3%。(2)4个样地植物根际土壤中AMF孢子分布不均匀,每克土的孢子密度在0.08～6.84个,平均为1.5个。对4个样地均有分布的狼牙刺、博落回、山蒿和秦岭风毛菊的AMF、DSE侵染状况调查发现,轻度和中度的铅锌污染能促进AMF与宿主共生关系的建立,而重度污染则显著抑制AMF侵染;AMF孢子密度没有呈现一定的规律性,且与AMF侵染率之间没有显著相关性;DSE侵染率与土壤锌含量存在显著正相关关系(r=0.505,P<0.05),而与土壤铅含量没有显著相关性。可见,AMF和DSE能够广泛存在于铅硐山铅锌矿区,尤其是DSE表现出较强的耐受性和适应性。     

土壤铅和锌对植物根际丛枝菌根真菌分布的影响

从秦岭凤县铅锌污染区4种植物根际共鉴定出球囊霉属(Glomus)丛枝菌根真菌(Arbuscular mycorrhizal ungi,AMF)12种,其中缩球囊霉(G.constrictum)是该区域的优势种;缩球囊霉、副冠球囊霉(G.coronatum)、苏格兰球囊霉(G.caledonium)和聚丛球囊霉(G.aggregatum)对铅锌污染具有较强的耐性,而地球囊霉(G.geospo-rum)、台湾球囊霉(G.formosanum)、地表球囊霉(G.versiforme)和两型球囊霉(G.dimorphicum)对铅锌污染的耐性较弱.相关分析表明,土壤Pb、Zn、速效P浓度和pH较低时,对AMF丰度有一定的促进作用,当Pb、Zn、速效P浓度和pH较高时,对AMF丰度为抑制作用,AMF丰度与高浓度Pb呈极显著负相关,与高浓度速效P呈显著负相关.通径分析表明,Pb是影响秦岭重金属污染区AMF丰度的主要因素,其直接和间接作用都较大,而pH、速效P和Zn主要通过Pb的间接作用来影响AMF丰度.     

铅锌砷复合污染对水稻生长的影响

铅锌砷复合污染对水稻生长的影响谢正苗,黄昌勇（浙江农业大学土化系杭州,３１００２９）ＥＦＦＥＣＴＳＯＦＣＯＭＢＩＮＥＤＰＯＬＬＵＴＩＯＮＯＦＬＥＡＤＺＩＮＣＡＲＳＥＮＩＣＯＮＲＩＣＥＧＲＯＷＴＨＸｉｅＺｈｅｎｇｍｉａｏＨｕｎａｇＣｈａｎｇｙｏｎｇ（Ｚ...     

一株耐铅镉真菌的分离鉴定及其吸附特性的研究

【目的】以扎龙湿地污染的土壤为材料,进行耐铅镉菌株的分离鉴定,研究不同条件对菌株吸附铅镉的影响。【方法】采用平板划线法,逐级驯化,筛选出一株耐铅镉菌株,通过生理生化特征及ITS序列分析对菌株进行鉴定,探究该菌吸附的最佳条件,并进行Langmuir和Freundlich等温吸附模型拟合。【结果】本研究分离得到一株菌株JB15,最高耐受浓度为Pb²⁺1200 mg/L、Cd²⁺200 mg/L,经鉴定为球孢白僵菌,最佳吸附条件温度为30°C,pH为7.0,接菌量为8.0 g/L,吸附时间为60 min,铅镉吸附率分别为52.27%和62.38%;铅镉吸附量分别为19.60 mg/g和3.98 mg/g,符合Langmuir等温吸附模型。【结论】菌株JB15具有较好的吸附效果,可为微生物修复重金属土壤污染提供理论基础。     

酿酒酵母220菌株对铅的生物吸附研究*

在含铅培养基中培养酿酒酵母220,发现该菌对铅有一定的抗性。将培养好的酿酒酵母220接入含铅培养基中并对该菌吸附铅的能力进行研究,结果表明,在30℃时,该菌对6mg/L的含铅溶液有最大的吸附率,吸附率为96．6％,吸附平衡时间为25～30min,吸附的动力学方程为q=26．318C／(1 0．437C),乙酸对吸附后的酿酒酵母220有良好的解吸作用,葡萄糖和KH2PO4可以提高酿酒酵母220对铅的吸附率。     

Cu(II) and Zn(II) ions alter the dynamics and distribution of Mn(II) in cultured chick glial cells

Previous studies revealed that Mn(II) is accumulated in cultured glial cells to concentrations far above those present in whole brain or in culture medium. The data indicated that Mn(II) moves across the plasma membrane into the cytoplasm by facilitated diffusion or counter-ion transport with Ca(II), then into mitochondria by active transport. The fact that 1–10 M Mn(II) ions activate brain glutamine synthetase makes important the regulation of Mn(II) transport in the CNS. Since Cu(II) and Zn(II) caused significant changes in the accumulation of Mn(II) by glia, the mechanisms by which these ions alter the uptake and efflux of Mn(II) ions has been investigated systematically under chemically defined conditions. The kinetics of [⁵⁴MN]-Mn(II) uptake and efflux were determined and compared under four different sets of conditions: no adducts, Cu(II) or Zn(II) added externally, and with cells preloaded with Cu(II) or Zn(II) in the presence and absence of external added metal ions. Zn(II) ions inhibit the initial velocity of Mn(II) uptake, increase total Mn(II) accumulated, but do not alter the rate or extent Mn(II) efflux. Cu(II) ions increase both the initial velocity and the net Mn(II) accumulated by glia, with little effect on rate or extent of Mn(II) efflux. These results predict that increases in Cu(II) or Zn(II) levels may also increase the steady-state levels of Mn(II) in the cytoplasmic fraction of glial cells, which may in turn alter the activity of Mn(II)-sensitive enzymes in this cell compartment.     

Transition metal-saccharide chemistry: d-glucose complexes of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)

Metal complexes of d-glucose (d-Glc) from large cation containing dibromo-dichloro salts of dipositive metals [NEt₄]₂[MBr₂Cl₂] (M = Mn, Co, Ni, Cu and Zn) and the disodium salt of glucose were synthesized from a MeOH:MeCN mixture. The complexes were characterized by UV-vis absorption, circular dichroism, IR and proton magnetic resonance spectroscopies, and by elemental analysis, and were found to be Na[M(d-Glc)(OMe)Cl]. Cyclic voltammetric studies of these complexes, in the acidic to neutral pH range, indicated no dissociation, even in highly acidic conditions.This paper is dedicated to Professor Richard H. Holm (Harvard University) on the occasion of his 60th birthday.     

抗铅锌功能菌生长菌株和干菌体吸附Pb2+、Zn2+性能优化及机理分析

【目的】针对湖南资兴铅锌矿污染问题,筛选本土耐性菌株用作生物修复。【方法】供试菌株J3筛选自湖南资兴铅锌矿区的尾砂矿矿渣,利用正交实验分析其生长菌株及干菌体最佳吸附条件以优化其吸附效果,同时对相关数据进行动力学拟合以探讨其吸附机理,最后结合形态观察和18S rRNA基因序列分析对其进行分类鉴定。【结果】在最佳条件下,J3生长菌株对Pb2+和Zn2+的去除率分别为92.2%和87.7%;干菌体对Pb2+和Zn2+去除率分别为72.6%和23.8%,反应动力学模型研究表明,生长菌株吸附过程中吸附速率受重金属浓度影响,对Zn2+吸附主要为颗粒内扩散作用;干菌体对Pb2+吸附推测为膜扩散和颗粒内扩散作用,而对Zn2+的吸附则由膜扩散控制。根据形态特征和系统发育分析,J3初步鉴定为虫生轮枝菌。【结论】生长菌株吸附效果好于干菌体,二级动力学方程拟合结果可为生物吸附反应器的设计提供理论参考和实践指导。     

Sorption of Cd(II) and Pb(II) by exopolymeric substances (EPS) extracted from activated sludges and pure bacterial strains: Modeling of the metal/ligand ratio effect and role of the mineral fraction

The present study deals with the sorption of Cd(II) and Pb(II) by exopolymeric substances (EPS) extracted from activated sludges or pure bacterial strains. The percentage of sorbed metal increases with the concentration of the EPS–water solution. Pb(II) always presents a higher affinity than Cd(II) for EPS. For the EPS extracted from pure bacterial strains, only one global binding constant from a simple equilibrium sorption model, may be used to assess the effect of microbial products such as EPS on Cd(II) and Pb(II) speciation or mobility in the environment. However, for EPS extracted from activated sludges, the wide variation of the global binding constants determined for Cd(II) and Pb(II) do not permit such a simple approach. The differences in sorption to metals between the two types of EPS (bacterial, activated sludges) could be explained by the differences in EPS composition: organic macromolecules, as well as the nature of the mineral fraction.     

Computer simulation of Zn(II) speciation and effect of Gd(III) on Zn(II) speciation in human blood plasma

The speciation and distribution of Zn(II) and the effect of Gd(III) on Zn(II) speciation in human blood plasma were studied by computer simulation. The results show that, in normal blood plasma, the most predominant species of Zn(II) are [Zn(HSA)] (58.2%), [Zn(IgG)](20.1%), [Zn(Tf)] (10.4%), ternary complexes of [Zn(Cit)(Cys)] (6.6%) and of [Zn(Cys)(His)H] (1.6%), and the binary complex of [Zn(Cys)₂H] (1.2%). When zinc is deficient, the distribution of Zn(II) species is similar to that in normal blood plasma. Then, the distribution changes with increasing zinc(II) total concentration. Overloading Zn(II) is initially mainly bound to human serum albumin (HSA). As the available amount of HSA is exceeded, phosphate metal and carbonate metal species are established. Gd(III) entering human blood plasma predominantly competes for phosphate and carbonate to form precipitate species. However, Zn(II) complexes with phosphate and carbonate are negligible in normal blood plasma, so Gd(III) only have a little effect on zinc(II) species in human blood plasma at a concentration above 1.0×10⁻⁴ M.     

Time-dependent Translational Response of E. coli to Excess Zn(II)

Zinc homeostasis is not well understood beyond methods of import and export. In order to better understand zinc homeostasis in Escherichia coli by identifying Zn(ii)-responsive proteins, a proteomic approach was taken. Through the use of two-dimensional gel electrophoresis, we were able to show that the levels of OmpF, AspC, YcdO, Eno, and CysE increased after 30 min of Zn(ii) stress, while the levels of Tig, TufA, SelA, and LeuC decreased relative to non-stressed controls. After 4 h of Zn(ii) stress, the levels of three proteins (DnaK, YeaU, and Mdh) were found to be up-regulated, while the levels of seven amino acid importers (HisJ, ArgT, LivJ, DppA, OppA, RbsB, and GinH) were found to be decreased. None of these proteins had been reported to be up- or down-regulated in any previously published cDNA microarray experiments. This result raises questions about the validity of cDNA arrays when they are used to make assumptions concerning protein levels within bacterial cells. These data also suggest that time is a factor when characterizing how the E. coli proteome responds to Zn(ii) stress.     

Synthesis, structures, and luminescence properties of mixed ligand Cd(II) and Zn(II) coordination compounds mediated by 1,2-bis(4-pyridyl)ethane

Interaction of cadmium(II) or zinc(II) acetate with 1,2-bis(4-pyridyl)ethane (bpe) in the presence of dioxime(1,2-cyclohexanedionedioxime = NioxH₂ or diphenylglyoxime = dpgH₂) resulted in three complexes with the compositions [Cd₂(CH₃COO)₄(NioxH₂)₂(bpe)(H₂O)₂] (1), [Cd(CH₃COO)₂(bpe)(H₂O)]_n (2) and [Zn(CH₃COO)₂(NioxH₂)(bpe)(H₂O)]_n (3), which were characterized by single-crystal X-ray diffraction, elemental analysis, IR, and luminescence spectroscopy. Dioxime-containing binuclear molecule 1 and 1D linear polymer 3 possess moderate luminescence properties, while the dioxime-free 1D polymer 2 demonstrates strong blue luminescence.     

Two-dimensional coordination polymers of Zn(II) and Cd(II) derived from 3,3′,5,5′-azobenzenetetracarboxylic acid exhibiting solvent facilitated structure reversibility

Two Cd(II) and Zn(II) coordination polymers based on 3,3′,5,5′-azobenzenetetracarboxylic acid (H₄abtc): [Cd₂(abtc)(H₂O)₆]·DMF·0.5H₂O (1) and [Zn₂(abtc)(bpy)(H₂O)₂]·DMF·H₂O (2) are synthesized and structurally characterized. Both 1 and 2 are 2D polymers but interconnected by solvent molecules to generate 3D suprastructures. Solvent expulsion leads to rupture of both structures, but upon re-exposure to the solvent mixture they exhibit remarkable ability to regain the original structure reversibly from the almost amorphous solvent-expelled form. Compounds with such structural flexibility and reversibility are expected to have some useful functionality.     

Zn(II) and Hg(II) complexes of naphthalene based thiosemicarbazone: Structure and spectroscopic studies

Synthesis, structure and spectroscopic characterization of 2-thiophenealdehyde-N(4)-napthylthiosemicarbazone and its complexes with biologically important Zn(II) and toxic Hg(II) metal ions have been reported. The crystal structure of the complexes reveals that both are distorted tetrahedral. In the Hg(II) complex the ligand is neutral and mondented where as in Zn(II) complex the ligand is bidented and anionic. Whereas conductivity measurement study shows both the complexes are molecular species. The beautiful changes in absorption spectra along with isosbestic points upon addition of respective metal salts to the ligand solution convincingly support the formation of metal complexes in solution phase. The other spectroscopic studies also show good correlation with their solid state structures.