利用高效转座质粒克隆Streptinomonas maltophilia YHJ-1的分解羽毛相关基因

嗜麦芽窄食假单胞菌Streptinomonas maltophilia YHJ-1是一株能高效降解羽毛角蛋白的菌株；该菌对卡那霉素等多种抗生素不敏感。本实验利用携带Tn5转座酶和卡那霉素抗性转座质粒pRL27和含氯霉素抗性基因盒的pMCm质粒，构建了以氯霉素抗性作为选择标记的转座质粒pRH30。以E. coli UQ3021/pRH30为供体，通过双亲本杂交，构建了S. maltophilia YHJ-1的插入突变体文库，该库共含1246个转化子。随机挑选4个突变子的氯霉素抗性检测和PCR扩增测序分析结果显示文库是可靠的。已从文库中筛选出3株不能降解羽毛转化子，表明利用氯霉素抗性的转座质粒pRH30来构建菌株YHJ-1的突变体是克隆其相关基因并进行遗传分析的有效方法。     

输液器污染微生物辐射抗性频率分布的研究

从 5 6套输液器分离得到 3 0 3 2株分离菌 ,系统地研究了输液器上污染微生物的辐射抗性。用辐射处理获得了较高抗辐射的微生物 98株 ,测定了它们的辐射抗性D10 。分离菌株的D10 是在 0 8～ 4 0kGy之间 ,主要集中在 1 2～ 1 6kGy。D10 ≤1 6kGy占全部污染菌的 99%。所有辐射筛选菌株是革兰氏阳性菌 ,其中 84株是Bacillussp .,1 4株是micrococcussp .。在输液器外壁获得了 1株桔红色的菌株 ,其D10 为 4 0kGy。     

两株抗苯菌灵稻瘟病菌突变体的若干特性

用由稻瘟病菌gp d基因启动子和终止子序列控制的、以粗糙脉孢菌的微管蛋白β-tubu lin(Bm 1)突变基因为选择标记的表达载体,转化稻瘟病菌0742野生型菌株,获得了两株具有苯菌灵抗性的菌株M 1和M 2。但Sou thern杂交表明,这两个菌株并不是由于质粒转化而获得苯菌灵抗性。对稻瘟病菌0742野生型及突变体M 1、M 2的β-tubu lin基因的序列比对分析表明,突变体M 1在内源β-tubu lin基因的第56、178、1704位置上发生了点突变,M 2在第56、899、1040、1389、1704位置上发生了点突变,导致M 1的352位氨基酸由苏氨酸变成了丙氨酸,M 2的107、154、270、352位氨基酸分别由苏氨酸、赖氨酸、苯丙氨酸、苏氨酸变为丙氨酸、谷氨酸、丝氨酸、丙氨酸。计算机分析显示M 1和M 2突变体β-tubu lin基因编码的蛋白质疏水性发生了微弱改变,结构域没有受到影响。该发现为开发新的稻瘟病菌遗传选择标记提供依据。     

土壤中“接力反硝化”机制的部分证据

设想土壤中存在不同类型的不完全反硝化细菌 ;这些细菌可以彼此配合 ,此菌产物作为彼菌的底物 ,共同完成完整的反硝化过程。该机制称之为“接力反硝化”机制 ,有别于传统的反硝化机制。本文为“接力反硝化”机制的存在提供部分证据。以土壤浸提液为培养基、N2 O为电子受体富集土壤微生物 ,获得了 1株仅完成NO-3 →NO-2 反应的细菌 (原始编号 2 1 6 9 2 )、1株仅完成NO-2 →N2 O反应的细菌 (原始编号 1 9 5 3)、1株仅完成NO-2 →N2 O→N2 反应的细菌 (原始编号 2 1 6 3 6 )。把菌株 2 1 6 9 2和 1 9 5 3两菌株以适当的数量比例混合于灭菌的土壤中 ,不添外来碳源 ,仅添加NO-3 ,厌气培养 1周后 ,测得土壤中剩余的NO-3 仅为原添加量的 39 4 %～ 5 3 0 % ,与此同时有 5 2 %～ 13 9%的NO-3 被还原成NO-2 ,有 2 8 6 %～ 30 8%以N2 O形态被回收 ,总回收率为 75 4 %～ 95 5 % ,说明两者可以相互配合 ,菌株 2 1 6 9 2的硝酸根还原产物可以被菌株 1 9 5 3用作底物 ,共同完成反硝化过程 ,从而支持我们设想的“接力反硝化”机制。     

西北部分矿区豆科植物根瘤菌重金属抗性及16S rDNA RFLP分析

从生长在西北部分矿区的豆科植物根瘤中分离筛选到对重金属有抗性的38株根瘤菌,采用PCR-RFLP分子技术进行16S rDNA指纹图谱分析,选取每种类型的代表菌株进行16S rDNA全序列测定,建立系统发育树状图,并对38株菌进行Zn、Hg、Cu、Cd和Pb5种重金属的抗性研究。结果表明,供试菌株分别归属于中华根瘤菌属（Sinorhizobium）、根瘤菌属（Rhizobium）和土壤杆菌属（Agrobacterium）。代表菌株CCNWSX1277和CCNWSX1294可耐受2.0mmol·L-1的Zn2＋,CCNWSX1277可耐受0.25mmol·L-1的Hg2＋,多数代表菌株可耐受1.6mmol·L-1的Cu2＋,仅3株代表菌株可以耐受Cd2＋,其中CCNWSX1277能耐受1.4mmol·L-1的Cd2＋,所有代表菌株能耐受2.5mmol·L-1的Pb2＋。Agrobacterium属的2株代表菌株对5种重金属均有较强的耐受性;而Rhizobium属的4株菌和Sinorhizobium属的3株菌对5种重金属的耐受性不同,表现出较大的差异。总体来看,供试菌株对重金属的耐受性顺序为Agrobacterium〉Rhizobium〉Sinorhizobium。     

黑曲霉对重金属Cu（Ⅱ）和Zn（Ⅱ）的抗性及富集特性

以黑曲霉（Aspergillus niger）为实验菌株,探讨不同pH值、重金属离子初始浓度、孢子液接种量和重金属离子共存对菌体生长量和富集能力的影响。结果表明：Cu（Ⅱ）和Zn（Ⅱ）对黑曲霉的最低抑菌浓度分别为250、700mg·L-1;菌株最佳生长和富集条件为pH5.0、孢子液体积1mL,黑曲霉对Cu（Ⅱ）和Zn（Ⅱ）的富集分别在4d和5d达到平衡。在重金属共存系统中,Cu（Ⅱ）/Zn（Ⅱ）浓度越高,黑曲霉对Cu（Ⅱ）/Zn（Ⅱ）富集能力越强;Cu（Ⅱ）和Zn（Ⅱ）的富集量分别在其浓度为150、250mg·L-1时达到最大（8.89、22.80mg·g-1）。采用扫描和透射电镜观察富集前后菌体表面形态和内部结构变化,表明菌体生长受重金属毒害作用可能破坏菌丝表面结构,A.niger富集Cu（Ⅱ）和Zn（Ⅱ）由表面吸附和胞内富集两部分组成,Zn（Ⅱ）作用下菌丝的完整性较好,菌株对Zn（Ⅱ）具有较强的抗性和适应能力。     

Frankia菌株At4的类nodD基因的克隆与研究

通过功能互补法从Frankia菌株At4的基因文库中筛选到可互补豌豆根瘤菌nodD基因功能的pAt2GX和pAt3GX,把pAt2GX和pAt3GX重新导入tmdD突变体中,接种豌豆苗,可观察到nodD突变体恢复了结瘤功能。扫描电镜观察、根瘤内生菌抗性标记检测及内生菌重组质粒的酶切分析均表明nadD突变体恢复结瘤功能是山于带有外源质粒pAt2GX和pAt3GX所致,这就证明了pAt2GX和pAt3GX带有类nodD基因功能的DNA片段。酶切分析及DNA-DNA杂交实验结果说明pAt2GX和pAt3GX不属于同—克隆,但这两个质粒的DNA之间有同源区。     

耐铜苏丹草根内生细菌的分离筛选及其生物学特性研究

从生长在铜矿废弃地土壤中的Cu耐性苏丹草根中分离筛选到二株产1-氨基环丙烷-1-羧酸(ACC)脱氨酶内生细菌K1-6和K3-9菌株,并对菌株生物学特性进行了研究。菌株K1-6和K3-9具有较强的Cu抗性和多种抗生素抗性,菌株K1-6和K3-9能够溶磷和分泌吲哚乙酸(IAA),另外,菌株K3-9还能够产生铁载体和精氨酸脱羧酶,菌株K1-6和K3-9对温度、p H和盐浓度具有一定的耐受性,经16S r DNA序列分析,菌株K1-6和K3-9分别被鉴定为根瘤菌属(Rhizobium sp.K1-6)和肠杆菌属(Enterobacter aerogenes K3-9)。采用平皿培养试验研究了菌株K1-6和K3-9对生长在不同浓度Cu(0、4 mg/L)环境中的苏丹草的生长和吸收Cu的影响。结果表明,接菌处理苏丹草根部和地上部干重分别比对照增加了10.6%~45.5%和13%~40%,差异达显著水平(P0.05);接菌株K1-6处理苏丹草根部和地上部Cu含量比对照增加了46%和85%(P0.05),而接菌株K3-9处理苏丹草根部和地上部Cu含量与对照相比没有显著差异。另外,接菌株K1-6处理苏丹草根部和地上部总Cu吸收量比对照增加了88%和114%(P0.05),接菌株K3-9处理苏丹草根部总Cu吸收量比对照增加了44%(P0.05)。另外,接菌株K1-6和K3-9处理的苏丹草根部吸收的Cu是地上部吸收Cu的16~23倍。研究表明,分离自耐铜苏丹草根部的内生细菌具有多种植物促生特性,能够显著促进苏丹草的生长、提高苏丹草对Cu的耐受性,并强化苏丹草根部对Cu的富集能力。另外,不同的内生细菌对苏丹草的生长、富集和耐受Cu的影响不同。     

马铃薯细菌多样性解析及促生高产 IAA菌株的筛选

采用 3种不同的培养基从马铃薯根际土壤和叶片中共分离出 78株细菌，优势菌属是 Pantoea，占菌株总数的 55.13%。马铃薯根际土采用 R2A培养基(27株优势菌，13个菌属)分离的细菌多样性相对较好，阿须贝培养基(31株优势菌，9个菌属)次之，土壤浸提液培养基(1株优势菌，1个菌属)最少；马铃薯叶片内生菌用阿须贝培养基(19株优势菌，3个菌属)分离的细菌多样性较差。采用 Salkowski比色液显色法定量测定菌株产 IAA能力，结果表明有 58株细菌具有分泌 IAA的能力，占测定菌株总数的 74.36%，从马铃薯根际土(42株优势菌，13个菌属)筛选的产 IAA菌数量及细菌多样性均高于马铃薯叶片内生菌(16株优势菌，2个菌属)。根据菌株产IAA能力强弱和分离部位及分离培养基的差异，选择 7株产 IAA菌进行促生特性和马铃薯盆栽幼苗促生能力等研究，结果显示:有 6株产 IAA菌具有 ACC脱氨酶能力，1株产 IAA菌具有溶解无机磷能力，2株产 IAA菌具有溶解有机磷能力；两轮温室促生实验结果显示，菌株 Pantoeasp.MLS-34-25对马铃薯幼苗具有明显的促生作用，是生产微生物肥料的潜在菌种。     

镉抗性植物内生菌EB12-6菌株的筛选及去除Cd~(2+)的初步研究

从生长于沈抚污灌区的野生东方蓼、狗尾草、稗草、山莴苣等植物组织中分离纯化出46株植物内生菌,经用含Cd~(2+)培养基筛选,得到对重金属镉具有较强抗性的细菌菌株EB12-6。观察其形态特征,研究对Cd~(2+)去除情况以及温度、p H、O_2、Na Cl对菌株生长的影响,结果表明:EB12-6菌株为好氧革兰氏阴性菌,有鞭毛;在p H为7.5,37℃温度,培养时间36 h,初始Cd~(2+)浓度为20 mg/L条件下,对Cd~(2+)去除率可达63.88%。     

The source of Pb,Cu, and Zn in fogwater

The variation in the concentrations of Zn, Pb, and Cu in water and acid extracts of airborne particulates and in fogwater collected in the rural northern San Joaquin Valley of California during the fall and winter of 1983–1984 was determined by anodic stripping voltammetry. There is a good correlation between water extracts of airborne particulates and fogwater for the concentrations of Cu and Pb and the concentration ratio (Cu/Pb), suggesting that the concentrations of these metals in fogwater is controlled by the concentration of extractable metal in the particulates on which the fog droplet forms. The major ion composition of the fogwater samples was measured by ion chromatography and compared with literature values for urban fogwater.     

Cu-tolerant Sinorhizobium meliloti strain is beneficial for growth,Cu accumulation,and mineral uptake of alfalfa plants grown in Cu excess

In this work, we have compared the physiological responses of alfalfa plants inoculated with either Sinorhizobium meliloti strain S412 (Cu-tolerant) or S112 (Cu-sensitive) in the presence or absence of 0.5 mM of CuSO₄. The addition of copper (Cu) introduced a decrease of nodule number and their dry weight (DW) in both symbioses. The interaction established with the Cu-sensitive strain is more affected by Cu than that with the tolerant one. In fact, plants inoculated with the sensitive strain revealed a decrease of shoot and root DW, larger than that found in plants inoculated with the tolerant strain. However, under copper supply, Medicago sativa with the Cu-tolerant strain did not show any significant changes in both shoot and root biomass production. Under Cu excess, high levels of Cu were detected in different parts of the plant in the two symbioses and a high translocation of Cu to aerial parts was shown with the strain S412. Plants with S412 were able to accumulate large quantities of calcium (Ca) in their roots and nodules. While Ca content decreased drastically in shoot at 0.5 mM of Cu treatment. Moreover, nodulation with S412 allowed plants to maintain high levels of magnesium (Mg) in all tissues and high iron (Fe) levels in nodules. Results suggest that this symbiotic pair could be used in phytostabilization of Cu-contaminated soils.     

Solubility control of Cu, Zn, Cd and Pb in contaminated soils

We developed a semiempirical equation from metal complextion theory which relates the metal activity of soil solutions to the soil's pH, organic matter content (OM) and total metal content (MT). The equation has the general form: where pM is the negative logarithm (to base 10) of the metal activity, and a, b and c are constants. The equation successfully predicted free Cu²⁺ activity in soils with a wide range of properties, including soils previously treated with sewage sludge. The significant correlation of pCu to these measured soil properties in long-contaminated soils suggests that copper activity is controlled by adsorption on organic matter under steady state conditions. An attempt was made from separate published data to correlate total soluble Cu, Zn, Cd and Pb in soils to soil pH, organic matter content and total metal content. For Cu, the total Cu content of the soil was most highly correlated with total soluble Cu. Similarly, total soluble Zn and Cd were correlated with total metal content, but were more strongly related to soil pH than was soluble Cu. Smaller metal solubility in response to higher soil pH was most marked for Zn and Cd, metals that tend not to complex strongly with soluble organics. The organic matter content was often, but not always, a statistically significant variable in predicting metal solubility from soil properties. The solubility of Pb was less satisfactorily predicted from measured soil properties than solubility of the other metals. It seems that for Cu at least, solid organic matter limits free metal activity, whilst dissolved organic matter promotes metal solubility, in soils well-aged with respect to the metal pollutant. Although total metal content alone is not generally a good predictor of metal solubility or activity, it assumes great importance when comparing metal solubility in soils having similar pH and organic matter content.     

茶苗对重金属Pb Cu Cd和Cr的吸收累积规律

通过盆栽实验,从动态角度研究了在不同培养期内,Pb、Cu、Cd和Cr4种重金属在茶树中的累积规律。结果表明,茶树不同部位对4种重金属的累积量存在很大差异,重金属的分布顺序为根〉茎〉叶;4种重金属大部分被茶树根系固定,在其体内的迁移性较低,在茶叶中积累的顺序为：Cr〉Cu〉Cd〉Pb。茶叶中重金属累积量和重金属添加量、培养时间都存在显著的正相关关系。4种重金属元素中,Cr的累积速率常数最大,Cd最小。茶树对重金属的吸收与土壤pH值和土壤有效态重金属含量显著相关。本研究可为人们科学认识茶叶中重金属的残留问题、健康风险及其污染控制提供理论依据。     

外源油菜素内酯介导Cu胁迫下番茄生长及Cu、Fe、Zn的吸收与分配

为了探索外源油菜素内酯对番茄Cu胁迫的缓解效应及机理,采用营养液水培的方法,以‘改良毛粉802F1’番茄为材料,研究外源2,4-表油菜素内酯(2,4-EBR,简称EBR)对Cu胁迫下番茄生长及矿质元素吸收的影响。结果表明:外源EBR能够缓解Cu胁迫对番茄植株的生长抑制。与Cu胁迫处理相比,喷施EBR的番茄叶绿素含量和生物量分别提高39.6%和20.0%,差异均达显著水平;Cu胁迫条件下,外源EBR显著降低番茄根系对Cu的吸收与转运,提高叶片中因Cu过多而降低的Fe、Zn含量,有效调控Cu、Fe、Zn的化学提取态和亚细胞分布水平,降低Cu在细胞内的生物毒性,使之向着有利于番茄生长的方向发展,从而保证Cu胁迫下植株正常的生理生化代谢。Cu胁迫提高了番茄叶片和根系各种化学形态的Cu含量,而外施EBR降低了番茄叶片中除NaCl提取态Cu以外的其他各种形态Cu含量。Cu胁迫下易移动态Cu在叶片中的比例升高,而根系中却下降;外施EBR后,番茄植株中难移动态和易移动态Cu的所占比例接近CK,说明Cu胁迫下EBR对Cu的番茄体内分配具显著调控作用。     

Cu,Co und Mo in Sesquioxid-Anreicherungshorizonten

Cu, Co and Mo in sesquioxide accumulation horizons Fe, Mn, Cu, Co and Mo were determined in 1) a podzol-gley- and 2) a pseudogley brownearth — stagnogley — ?ochre earth”?-landscape. In landscape 1) the accumulation of Fe in the gley — G_o is pronounced and the translocation Mn>Cu, whereas landscape 2 is characterized by the accumulation of Mn in the ?ochre earth”? and by a translocation Co>Cu (Mo shows just small differences in 1) and 2)). The relation between the distribution of Cu, Co and Mo and of sesquioxides is overlapped by the influence of organic matter. From larger concentration differences for both Mn and Co in landscape 2 as compared to 1 a special role of manganese oxides for the accumulation of Co can be concluded. This accumulation however is not connected with a stronger immobilization.     

温州城市土壤Cu,Zn,Pb含量及其形态研究

分别采集了温州市区风景区、交通干线、住宅区、文教区、工业区土壤样品21个,郊区农田保护区土壤样品2个,测定了各土壤样品的基本理化性质和Cu,Zn,Pb,Cd含量。结果表明:各土样Cu,Zn,Pb的平均含量分别为(34.59±18.29)mg/kg,(169.40±52.97)mg/kg,(65.22±26.86)mg/kg,均超出温州土壤背景值。Cd仅在个别土样中检出,且浓度极低。各形态含量的分析结果表明,Cu,Zn,Pb均以残余态为主,分别为60.17%,50.95%,47.33%。Cu和Pb的酸提取态含量最低,Zn则是有机态含量最低。各形态含量与土壤基本理化性质的相关分析结果表明,Cu,Zn各形态与有机质含量的相关性最大,而Pb则与土壤基本理化性质之间无明显相关关系。     

不同品种水稻糙米对Cd Cu Zn积累特性的研究

以酸性矿山废水污染的含有多种重金属的农田土壤为供试土壤,通过盆栽实验,研究不同水稻品种,不同类型、不同遗传背景水稻糙米重金属Cd、Cu、Zn的积累差异。结果表明,供试水稻糙米Cd含量为0.006～0.092mg·kg-1,最高值和最低值相差15倍;Cu含量为6.712～27.117mg·kg-1,最高值和最低值相差4倍;Zn含量为28.390～43.296mg·kg-1,最高值和最低值相差不到1倍。常规稻和杂交稻糙米的Cd、Cu、Zn含量差异不明显。三系杂交稻的糙米Cd、Cu含量极显著高于二系杂交稻,而二系杂交稻糙米中Zn含量则显著高于三系杂交稻。不同遗传背景水稻品种糙米Cd、Cu、Zn含量也存在明显差异。相关分析结果表明,糙米中Cu、Cd含量间呈极显著正相关,Cu、Zn含量之间存在显著负相关,而Cd、Zn含量间的相关性不明显。