皮氏罗尔斯通氏菌株DX-T3-01的耐镉性能及镉富集机理

从江西德兴铜矿土壤中分离筛选到一株具有较强耐镉(Cd)能力的细菌DX-T3-01,经生理生态及16S rRNA分析进行鉴定,研究其对不同浓度Cd2+的耐受特性及对重金属Zn2+、Cu2+、Ni2+的耐受性,进一步利用扫描电镜-能谱仪(SEM-EDX)和红外光谱(FTIR)探讨菌株对Cd2+累积去除的机理.经鉴定,耐镉细菌DX-T3-01为皮氏罗尔斯通氏菌(Ralstonia pickettii);Cd2+最高耐受浓度(MTC)为16 mmol L-1,最低抑制浓度(MIC)为4 mmol L-1,并可耐受一定浓度的Zn2+、Cu2+;菌体积累Cd2+后细胞表面有沉淀物附着并有镉元素检出,对Cd2+的累积主要依靠细胞壁上—PO43-、胺基中的—C—N—、—M—O(O—M—O)、C=O和酰胺基(—CO—NH—)基团.图5参16     

Review: Biomechanics of Child Occupant Protection

This paper provides a review on the following issues: the differences in injury patterns between adults and children under similar loading conditions during an automotive crash event. Because of the recent awareness and the ensuing necessity, as an example, injuries including fatalities due to airbag deployment are discussed. Biomechanical differences explain the varying injury patterns and mechanisms of injury. The commonly adopted scaling techniques for predicting pediatric tolerances are described. A comparison of the biomechanical properties of the pediatric and adult structures is given. Some insight is provided with regard to the use of these data to develop validated mathematical models of pediatric structures. The paper concludes with recommendations for further research.     

Different survival of chromium-exposed Oxya chinensis among allozyme genotypes

The goal of the present study was to compare the different survival of Oxya chinensis exposed to chromium(Ⅵ) among allozyme genotypes to gain a better understanding of the relationship between the genetic variations and environmental disturbance. This study analyzed the occurrence of genotypes in O. chinensis population exposed to Cr(Ⅵ). O. chinensis samples were collected at Yuanping, Shanxi Province, China and used in acute toxicity tests. Specimens were assigned to Cr(Ⅵ) exposure (LD50: 291.0 mg/kg) for ...     

Seedling growth and metal accumulation of selected woody species in copper and lead/zinc mine tailings

A greenhouse pot experiment was conducted to evaluate the potential of selected woody plants for revegetation in copper (Cu) and lead/zinc (Pb/Zn) mine tailing areas. Five woody species (Amorpha fruticosa Linn, Vitex trifolia Linn: var. simplicifolia Cham, Glochidion puberum (Linn.) Hutch, Broussonetia papyrifera, and Styrax tonkinensis) and one herbaceous species (Sesbania cannabina Pers) were planted in Cu and Pb/Zn tailings to assess their growth, root morphology, nutrition uptake, metal accumulation, and translocation in plants. Amorpha fruticosa maintained normal growth, while the other species demonstrated stress related growth and root development. Sesbania cannabina showed the highest biomass among the plants, although it decreased by 30% in Cu tailings and 40% in Pb/Zn tailings. Calculated tolerance index (TI) values suggested that A. fruticosa, an N-fixing shrub, was the most tolerant species to both tailings (TI values 0.92–1.01), while S. cannabina had a moderate TI of 0.65–0.81 and B. papyrifera was the most sensitive species, especially to Pb/Zn tailings (TI values 0.15–0.19). Despite the high concentrations of heavy metals in the mine tailings and plants roots, only a small transfer of these elements to the aboveground parts of the woody plants was evident from the low translocation factor (TF) values. Among the woody plants, V. trifolia var. simplicifolia had the highest TF values for Zn (1.32), Cu (0.78), and Pb/Zn (0.78). The results suggested that A. fruticosa and S. cannabina, which have the highest tolerance and biomass production, respectively, demonstrated the potential for tailings revegetation in southern China.     

两种赤潮藻对SD和SMX的耐受性研究

探讨了海洋中常见药残磺胺嘧啶(SD)和磺胺甲恶唑(SMX)对球形棕囊藻和东海原甲藻生长的影响。结果表明:当这两种磺胺药物浓度大于20 mg/L时,球形棕囊藻和东海原甲藻的生长明显被抑制;SD和SMX对球形棕囊藻半数生长影响的浓度(EC50)分别为60～80 mg/L和20～40 mg/L;SD和SMX对东海原甲藻半数生长影响的浓度分别为20～40 mg/L和40～60 mg/L;两种藻培养96 h时扫描电镜观察,均显示高浓度下藻细胞膜严重破损,说明磺胺药物对其生长具有抑制作用。EC50对比表明球形棕囊藻对SD的耐受性强于SMX,而东海原甲藻对SMX的耐受性强于SD。两种藻对药残的耐受性明显强于其他藻种,在高浓度药残环境中占据生存优势。通过这项研究,试图探讨磺胺药物对河口及近海养殖区赤潮频发和赤潮消亡的影响。     

铜胁迫对3种草本植物生长和重金属积累的影响

采用盆栽试验,研究了不同浓度Cu胁迫对3种草本植物弯叶画眉草、象草和苏丹草生物量、根系耐性指数、Cu积累量、富集系数、转运系数的影响。结果表明,弯叶画眉草和象草生长随着Cu胁迫浓度的升高呈现"上升-下降"趋势,胁迫浓度低于100 mg·kg~(-1)时促进生长;苏丹草生长随着Cu胁迫浓度的增加而下降;弯叶画眉草、象草和苏丹草的Cu耐性指数分别是130.63、149.15和75.81。3种植物对重金属Cu均以根系积累为主,积累量随着Cu处理浓度的增加显著升高;对Cu的吸收和富集能力为象草苏丹草弯叶画眉草,Cu从根系转运到地上部的能力为弯叶画眉草象草苏丹草,转运系数均小于1。可见,象草耐性较强,可用于Cu污染土壤植物修复;弯叶画眉草转运能力较强,可用于Cu污染土壤生物净化。     

低温弱光条件下毒死蜱对黄瓜的毒性效应及油菜素内酯的调控作用

农药在使用中可能对农作物产生药害作用,而在低温弱光的亚适宜条件下,设施作物对农药暴露的应激响应可能具有特殊性。同时,作为一种新型植物激素,油菜素内酯在亚适宜条件下是否能够缓解农药的药害作用的研究有限。以典型的设施作物黄瓜为受试生物,通过人工气候箱模拟低温弱光的亚适宜条件,在毒死蜱(浓度分别为0.3和1mmol·L-1)暴露1、3和7d后,以实时荧光定量PCR对黄瓜叶片中光合作用基因(psaB、psbA和rbcL)、抗氧化系统相关基因(cAPX、DHAR、GR、CAT和GPX)、防御和应激相关基因(PAL、HPL、ADC和HSP70)的转录水平进行检测,阐明其毒性效应。并对比24-表油菜素内酯的预处理组,探讨油菜素内酯如何调控作物对农药胁迫的响应。结果表明,在低温弱光条件下,毒死蜱暴露抑制了黄瓜叶片中上述大部分基因的转录,而24-表油菜素内酯预处理后其转录水平显著上升,表明24-表油菜素内酯可有效且持续地缓解毒死蜱的药害效应。     

Developed fungal–bacterial biofilms as a novel tool for bioremoval of hexavelant chromium from wastewater

Remediation measures for hexavalent chromium [Cr(VI)] are required for a safe environment. As a recent development in microbiology, bacterial biofilms are being studied as effective bioremediation agents. When bacteria are in fungal surface-attached biofilm mode, they are called fungal–bacterial biofilms (FBBs). They have not been tested for bioremediation so far. Hence, this study was conducted to develop FBBs and glass-wool-attached bacterial biofilms (BBs), and to evaluate Cr(VI) tolerability and removal of bacterial monocultures, BBs and FBBs. FBBs showed a significantly high level of Cr(VI) tolerance and resistance compared with its BBs or monocultures. After 10 days, up to 90% of Cr(VI) had been removed, which was significantly higher than that of BBs or its monocultures. Thus, it is clear that FBBs can be used as a novel tool to decontaminate Cr(VI) both in situ and ex situ.     

Pb污染对白菜的生态毒理效应研究（Ecotoxicological Effects of Pb on Brassice rapa）

采用水培方法研究了白菜种子和幼苗对Pb的富集能力与耐受性.实验设6个处理浓度,分别为0.2mg·L-1、0.4mg·L-1、0.8mg·L-1、1.6mg·L-1、3.2mg·L-1及对照,共培养7d,然后测定种子萌发抑制率、茎生长抑制率、根的耐性指数、叶绿素与类胡萝卜素含量与铅的富集量.研究表明白菜幼苗对高浓度的Pb具有富集能力,根是主要的富集器官,根的最高富集量为75.46mg·L-1.Pb抑制白菜幼苗的营养生长,抑制白菜根的伸长.0.2mg·L-1处理浓度下,Pb促进白菜茎的生长,高浓度的Pb抑制白菜茎的生长.Pb抑制白菜体内叶绿素a、叶绿素b和类胡萝卜素的含量.铅影响白菜幼苗的正常生长,白菜对铅具有一定耐受性.