Perfluorooctanoic Acid (PFOA): Environmental Sources,Chemistry, Toxicology,and Potential Risks

Attention regarding perfluoroalkyl and polyfluoroalkyl substances (PFAS) has increased in recent years, due to recognition of widespread environmental presence, recognition of a chemical structure that confers resistance to degradation, and reported health concerns. Historical common exposure sources include food, drinking water, occupational circumstances, and products in commerce (e.g., carpeting, clothing, paper products). Early-2000’s data showed perfluorooctanoic acid (PFOA) was present in blood samples from nearly all the U.S. general population (>99%). Alterations in industrial manufacturing processes, increased regulatory scrutiny, and advanced water treatment options have reduced the reported human body burden of PFAS in the U.S., including for PFOA. Human serum concentrations of PFOA, which do not identify the source(s) of exposure, have exhibited a substantial decrease (~63%) between the 1999–2000 and the 2013–2014 NHANES monitoring by the Centers for Disease Control and Prevention (CDC). With respect to both noncancer and potential cancer effects that may be associated with reported serum levels of PFOA, conclusions regarding an absence of effects, or insufficient information to suggest adverse effects, prevent a consistent conclusion about the occurrence and magnitude of human health effects. In the last several years, a number of state and federal agencies have developed health advisories or guideline values for drinking water exposure that are in the sub-ppb range. In 2016, a USEPA Health Advisory of 0.07 ppb was released, which stands in contrast to 2016 Health-based Values from Health Canada ranging from 0.2 ppb (PFOA) to 30 ppb, and a few other U.S. states with values even less than that of USEPA (e.g., MN, NJ, VT). Further work is necessary to distinguish in transparent fashion between drinking water levels that intentionally are set on a conservative basis to protect human health vs exposure levels that may be associated with tangible adverse effects.     

5种湿地植物对土壤重金属的富集转运特征

选择芦苇、水葱、千屈菜、扁秆藨草、长苞香蒲5种湿地植物进行盆栽实验,比较它们对土壤中的5种重金属镉、铬、汞、铅、锌的富集特性,分析重金属在各植物体和土壤中的动态分布,以评价所测植物对土壤中重金属的综合富集能力,为利用植物修复金属污染土壤提供理论依据和技术支持。结果表明:(1)种植湿地植物对土壤重金属的富集效果显著高于无植物对照,且随着处理时间的延长,土壤中重金属镉、铬、汞、铅、锌的含量均呈下降趋势。(2)湿地植物对重金属镉、铬、汞、铅、锌的富集效果差异显著,其中水葱根部对重金属镉的富集系数最大,芦苇根部对重金属铬、汞、铅、锌的富集系数均最大,千屈菜、扁秆藨草和长苞香蒲根部对5种重金属的富集系数均较小;芦苇地上部分对金属镉的富集系数最大,千屈菜地上部分对金属铬、汞、铅的富集系数均最大,水葱地上部分对金属锌的富集系数最大。(3)5种湿地植物对重金属镉、铬、汞、铅、锌的转移系数差异显著,其中扁秆藨草对土壤中镉、铬、铅、锌的转移系数均为最大,对铬和锌的转移系数均大于1,长苞香蒲对铬的转移系数大于1,仅次于扁秆藨草。其他3种植物对5种重金属的转移系数均小于1。研究表明,5种湿地植物对重金属Cd、Cr、Hg、Pb、Zn都有富集和转移的能力,但不同植物对不同重金属的富集效果不同。     

湿地植物与丛枝菌根真菌(AMF)相互关系的研究进展

丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)是湿地植物主要共生菌之一,在湿地生态系统中具有重要的作用.本文就近年来AMF对湿地植物的营养物质吸收、生长发育、抗逆境胁迫和抗污染能力等的作用,湿地植物、水分、季节、土壤理化性质因素对根际AMF的多样性、侵染能力、空间分布、生长发育、孢子密度的影响,以及植物与AMF之间相互作用关系的研究进展进行综述.     

Phytoremediation of iron from red soil of tropical region by using Centella asiatica

The accumulation and removal efficiency of Fe by Centella asiatica was carried out at various Fe concentrations in soil treatments (0, 50, 100, 150 and 200 mg Fe/kg soil). Iron accumulation in different parts of C. asiatica (leaf, stem and root) was analyzed by atomic absorption spectrophotometer (AAS). Factorial experiment with a completely randomized design and Duncan's test were used for data analyses. The results revealed that C. asiatica have the ability to uptake and accumulate Fe significantly (p < 0.05; r = 0.977) in the aerial parts. The different soil treatments had significant effect on the total Fe accumulations in C. asiatica (p < 0.05). The potential of C. asiatica as a metal hyperaccumulator plant, harvested for analysis, shows efficient accumulation of Fe at high concentration (p < 0.05; r = 0.977). The root showed the highest accumulation of Fe followed by the leaves (p < 0.05) and the stem (p < 0.05). The Pearson correlation coefficient between leaves and root have showed highly significant correlation (p < 0.01; r = 0.785) as compared to the leaves and stem (p < 0.01; r = 0.780). The efficiency of Fe removal by C. asiatica from the contaminated soil has been evaluated by bioconcentration factor and translocation factor, found to be >1 and <1, respectively, further supporting its metal hyperaccumulator properties.     

Accumulation of Heavy Metals in Water,Sediments and Wetland Plants of Kizilirmak Delta (Samsun,Turkey)

In this study, concentrations of heavy metals (Fe, Mn, Ni, Co, Zn, Cu, and Pb) were measured in water bodies including streams, bottom sediments and various wetland plants of K?z?l?rmak Delta. K?z?l?rmak Delta is one of the largest and the most important natural wetlands in Turkey and has been protected by Ramsar convention since 1993. The heavy metal concentrations in water were found lower than that of national standards for protected lakes and reserves. In bottom sediments and wetland plants, however, the accumulated amounts of different heavy metals varied in the following order: Fe>Mn>Zn>Ni>Co>Cu>Pb, and Fe>Mn>Zn>Ni>Co respectively. Heavy metal uptake of Hydrocharis morsus-ranae and Myriophyllum verticillatum plants among others were found far above the toxic levels and they might be used as bio-indicators and heavy metal accumulators in polluted natural areas.     

Phytoremedial Potential of Typha latifolia,Eichornia crassipes and Monochoria hastata found in Contaminated Water Bodies Across Ranchi City (India)

Phytoremediation is an emerging technology that uses green plants (living machines) for removal of contaminants of concern (COC). These plant species have the potential to remove the COC, thereby restoring the original condition of soil or water environment. The present study focuses on assessing the heavy metals (COC) present in the contaminated water bodies of Ranchi city, Jharkhand, India. Phytoremedial potential of three plant species: Typha latifolia, Eichornia crassipes and Monochoria hastata were assessed in the present study. Heterogenous accumulation of metals was found in the three plant species. It was observed that the ratio of heavy metal concentration was different in different parts, i.e., shoots and roots. Positive results were also obtained for translocation factor of all species with minimum of 0.10 and maximum of 1. It was found experimentally that M. hastata has the maximum BFC for root as 4.32 and shoot as 2.70 (for Manganese). For T. latifolia, BCF of maximum was observed for root (163.5) and respective shoot 86.46 (for Iron), followed by 7.3 and 5.8 for root and shoot (for Manganese) respectively. E. crassipes was found to possess a maximum BCF of 278.6 (for Manganese and 151 (for Iron) and shoot as 142 (for Manganese) and 36.13 (for Iron).     

Synthesis of Novel Plant Growth Inhibitors Structurally Related to Abscisic Acid

When paraffin wax is dispersed in medium as emulsion, some kinds of bacteria and yeasts readily grow on it. This paper presents a study on microbial cell production from solid paraffin. In this study a paraffin wax which contains 91% of normal paraffins ranging from C₂₅ to C₃₇ with the melting point of 62.5°C was used as a substate, but no solvent was used for the dispersion of the wax.

As a result of this study, the following have been found out. (1) Many strains of liquid normal paraffin assimilating bacteria and yeasts can assimilate paraffin wax. (2) Dried cell yields on added hydrocarbons of Corynebacterium hydrocarboclastus S-12-B2 and Candida tropicalis S-315-Y1 are 70% and 56% respectively, when they are cultured by wax emulsion of 0.6% concentration. (3) When nonion surface-active agent (Plysurf A210G) was added as an emulsifing agent, highly concentrated wax emulsion was obtained, but the growth of microorganisms on it was slower. Further investigation is needed to obtain better strains of bacteria and yeasts and also to find out optimum culture conditions.     

积累L-苹果酸的米根霉突变株酶活性初探

对富马酸产生菌株—米根霉ME-F10进行诱变育种的过程中, 得到一株性能稳定的高效积累L-苹果酸的突变株ME-M15。该菌株发酵96 h平均L-苹果酸产量达16.3 g/L, 较出发菌株L-苹果酸积累量平均提高3倍, 而富马酸和乙醇的积累量大幅下降。对突变株代谢途径关键酶活研究表明, 突变株富马酸酶胞质途径同功酶和乙醇脱氢酶活力较之出发菌株酶活力明显减弱, 而丙酮酸羧化酶活力无明显差别。     

不结球白菜维生素C积累与相关酶活性研究

对不结球白菜‘常州乌塌菜’、‘矮脚黄’和‘二青’生长过程中维生素C(AsA)含量和L-半乳糖酸-1,4-内酯脱氢酶(GalLDH)、抗坏血酸氧化酶(AAO)、抗坏血酸过氧化物酶(APX)、单脱氢抗坏血酸还原酶(MDAR)、脱氢抗坏血酸还原酶(DHAR)的活性进行测定分析,结果显示,AsA含量的积累呈先升高后下降的模式,且‘常州乌塌菜’中的AsA含量显著高于‘矮脚黄’和‘二青’;GalLDH活性与AsA含量变化趋势基本一致,且3个品种中GalL-DH活性与AsA积累之间均呈极显著的正相关关系;AAO和APX活性的变化趋势则与AsA含量变化趋势相反,而‘常州乌塌菜’中AAO活性显著低于其它2个品种,但APX活性无显著差异;MDAR和DHAR的活性则主要表现在生长后期。结果表明,不结球白菜中AsA含量主要受GalLDH酶活性调节,同时AsA代谢酶AAO也对AsA积累起到了重要作用,而MDAR和DHAR酶活性对AsA积累的作用主要在生长后期。     

螺旋藻乙醇酸氧化酶(GO)的研究

采用比色法对鄂尔多斯高原碱湖的钝顶螺旋藻(S1)与国外引进的钝顶螺旋藻(S2)和极大螺旋藻(S3)的乙醇酸氧化酶(GO)进行了比较研究。结果表明:在25℃、pH 8.0条件下,S1、S2和S3的GO活性分别为70.9 U/gFW、59.6 U/gFW和80.9 U/gFW;最适温度均为30℃;在0℃~35℃(30℃)范围内比较稳定;最适pH值分别为8.6、8.2和8.4;pH值稳定范围,S1为7.6~10.0、S2为8.0~9.0;S3为8.0~8.6。S1的GO对温度和pH适应范围最宽,且在低温、高温、强酸和强碱下的活性均比引进种的高。     

脱氧核糖核酸对谷胱甘肽过氧化物酶活性影响的初步研究

谷胱甘肽过氧化物酶是机体内重要抗氧酶系之一。它的活力和含量,反映机体清除自由基的能力。自由基对细胞结构的损伤很大,随着年龄的增长,抗氧化酶活力逐渐下降,从而引起自由基及脂质过氧化产物日益增多,最终导致机体衰老和老年性疾病的发生^[1]。本试验试图探讨DNA对谷胱甘肽过氧化物酶活性影响从而探索DNA对抗自由基的作用。     

L-乳酸的发酵生产和聚L-乳酸的化学加工

L-乳酸广泛应用于食品、医药、日化和工业等各个领域。近年来随着石化资源的不断紧缺,众多化学合成的高分子材料的生产受到了限制。以生物质资源为基础的L-乳酸因此被大量用于加工生产成聚L-乳酸等环境友好型生物可降解材料。正是由于L-乳酸需求量的增大,如何高效低成本地生产L-乳酸显得尤为重要。系统综述了L-乳酸生产菌株的选育,用于L-乳酸发酵生产的廉价资源的开发利用,L-乳酸的发酵生产和L-乳酸的分离纯化等方面的研究进展。目前研究的热点和难点正是基于上述四个部分:菌种方面,以可以高效代谢利用廉价底物,且营养需求低的选育目标获得了多个优良的生产菌种,然而具备综合代谢优势的菌种还有待进一步选育;发酵底物方面,已开发利用多种廉价,来源丰富且易于菌种代谢并高效转化成乳酸的底物,但是对这些底物工业规模应用还有待进一步研究;发酵工艺方面,建立了环境友好型,劳动强度低的发酵工艺,然而实际应用中仍然存在成本高的问题;后提取方面,通过选育低营养需求的生产菌种和采用新型发酵工艺有效地简化了后提取过程,但是实际应用方面仍受发酵工艺成本高的制约。最后对聚L-乳酸的化学加工以及聚L-乳酸的生物降解进行了探讨并提出了一些建议。     

Indigenous Medicinal Plants in Mexico: the Example of the Nahua (Sierra de Zongolica)

As in most peasant cultures medicinal plants are a very important resource for the Nahua of the Sierra de Zongolica (Mexico). Documentation of the current indigenous medicinal uses of 203 plants in this region was conducted during 18 months of fieldwork. The 816 individual reports documented were divided into nine groups of indigenous uses. The frequency of usage of the individual plants reported was employed in the analysis of the ethnobotanical importance of the respective plants. Plants cited more frequently in a group of indigenous uses are regarded as of greater ethnobotanical importance than those cited only by a few informants. Data on phytochemistry, pharmacology and ethnobotany from the scientific literature were used to evaluate possible biological or pharmacological and toxicological effects of some particularly important plants. For most plants detailed studies on these actions are still lacking, which would allow a conclusive evaluation. This ethnobotanical evaluation forms the basis for such studies which have been started on some plants, and for better understanding their potential as minor economic products of the region. These uses may also give incentives to the conservation of the local biodiversity.     

人小肠三叶因子（hITF）基因在生菜中的整合与表达

用根癌土壤杆菌（Agrobacterium tumefaciens(Smith et Townsend)conn)介导的叶盘法,将人小肠三叶因子（hITF)导入生菜（Lactuca sativa L.)中,在含有除草上培养基上筛选,获得抗性植株,通过PCR和Southern印迹分析证明,hITF cDNA已整合到生菜基因组中,Western印迹分析证明hITF在生菜中的表达。ELISA检测表明,hITF在生菜新鲜叶片中的表达量为200－300ng/g,最高达700ng/g,约占总可溶性蛋白的0．1％。     

Non-Involvement of the Human Monocarboxylic Acid Transporter 1 (MCT1) in the Transport of Phenolic Acid

Phenolic acids such asp-coumaric acid and microbial metabolites of poorly absorbed polyphenols are absorbed by the monocarboxylic acid transporter (MCT)-mediated transport system which is identical to the fluorescein/H⁺ cotransport system. We focus here on the physiological impact of MCT-mediated absorption and distribution. We examined whether MCT1, the best-characterized isoform found in almost all tissues, is involved in this MCT-mediated transport system. The induction of MCT1 expression in Caco-2 cells by a treatment with sodium butyrate (NaBut) did not increase the fluorescein permeability. Moreover, the transfection of Caco-2 cells with an expression vector encoding MCT1 caused no increase in either the permeability or uptake of fluorescein. Furthermore, in the MCT1-expressing oocytes, no increase ofp-coumaric acid uptake was apparent, whereas the uptake of salicylic acid, a substrate of MCT1, nearly doubled. Our data therefore establish that MCT1 was not involved in the MCT-mediated transport of phenolic acids.     

高效液相色谱法同时测定银凤桃中的赤霉素和脱落酸

赤霉素(GA3)和脱落酸(ABA)是果实组织中的两个重要激素,本试验用SymmetryC18色谱柱(4.6mm×150mm),以乙腈和1.8%乙酸[V(CH3CN)∶V(1.8%CH3COOH)=1∶1]为流动相,流速为0.5mL·min-1,Wa-ters2487UV-检测器,在检测波长254nm,柱温25℃的条件下,同时分离并测定了银凤桃中的GA3和ABA。GA3和ABA的分离效果理想,回收率分别达到100.1%和99.8%,该方法测量灵敏度达10-2ng·g-1,精密度RSD%<0.1。     

百喜草及其在南方果园生草栽培和草被体系中的应用

果园立地条件差、土壤肥力不足是影响我国果树产量和果实品质的重要因素。百喜草是优良的果园生草栽培和草被体系草种。在我国南方果产区推广应用百喜草,对于防止水土流失、改善果园生态环境、培肥果园土壤、提高果实产量和品质具有重要意义。     

喷施己酸二乙氨基乙醇酯对几种与番茄幼苗抗冷性相关生理指标的影响

番茄幼苗叶面喷施适宜浓度(20～40mg·L~(-1))的己酸二乙氨基乙醇酯(DA-6)可有效提高冷胁迫下番茄幼苗植株的抗寒能力。冷胁迫下,20～40mg·L~(-1)DA-6处理的番茄植株自由水/束缚水比值降幅较大,叶中叶绿素含量、超氧化物歧化酶(SOD)、过氧化物酶(POD)和抗坏血酸过氧化物酶(APX)活性也明显增大,丙二醛(MDA)积累下降25.8%～34.6%,可溶性糖和可溶性蛋白质含量提高。     

黄腐酸的提取与其醒酒作用的研究

提取制备黄腐酸(FA)并研究其醒酒作用及部分作用机制,对昆明小鼠预防性灌胃不同浓度的黄腐酸,观察小鼠的醉酒时间和醉酒小鼠的只数,并使用气相色谱仪(GC)测定小鼠血浆中乙醇的浓度。结果:与模型组相比,3%、5%黄腐酸组中小鼠醉酒时间明显缩短(P0.05);与海王金樽组相比,1%、3%、5%黄腐酸组中小鼠醉酒时间均明显缩短(P0.05),且5%黄腐酸的醒酒防醉效果最佳。与模型组相比,30、90min时,1%、5%黄腐酸组中小鼠血浆中乙醇浓度明显降低(P0.05);60min时,乙醇浓度降低非常明显(P0.01)。与海王金樽组相比,60、90min时,1%、5%黄腐酸组中小鼠血浆中乙醇浓度明显降低(P0.05)。黄腐酸具有醒酒作用,这为开发黄腐酸成为一种新型的醒酒药物提供了实验数据。