Quantitative Risk Assessment of Trichloroethylene for a Former Chemical Works in Shanghai,China

Assessment of the potential risks posed by chlorinated solvents in groundwater is the key to establish the extent of the contamination and derive achievable remedial targets should remediation deems necessary. This article first presents the application of the American Society for Testing and Materials (ASTM) Risk Based Corrective Actions (RBCA) Guidance to quantitatively evaluate human health and environmental risk for a former chemical works in Shanghai, China. The observed maximum trichloroethylene (TCE) concentration in groundwater at the site reached 1220 mg/l that exceeded its solubility of 1070 mg/l at 10°C (Soil annual average temperature is 10°C in Shanghai). The maximum concentration for cis-1, 2-DCE (DCE) was also found to be elevated at 264 mg/l. A critical exposure pathway was considered to be indoor vapor intrusion of TCE into the buildings with excess lifetime cancer risk for children being 1.7 × 10^?3. This cancer risk exceeded regulatory limits of 1 × 10^?4 to 1 × 10^?6 for The Netherlands, the United Kingdom, and the United States. The calculated groundwater remedial targets for TCE and DCE are 7 mg/l and 904 mg/l, respectively, in order to protect child residents from inhalation of indoor vapors within the close proximity of the source area.     

Toward routine,DNA-based detection methods for marine pests

Marine pest incursions can cause significant ongoing damage to aquaculture, biodiversity, fisheries habitat, infrastructure and social amenity. They represent a significant and ongoing economic burden. Marine pests can be introduced by several vectors including aquaculture, aquarium trading, commercial shipping, fishing, floating debris, mining activities and recreational boating. Despite the inherent risks, there is currently relatively little routine surveillance of marine pest species conducted in the majority of countries worldwide. Accurate and rapid identification of marine pest species is central to early detection and management. Traditional techniques (e.g. physical sampling and sorting), have limitations, which has motivated some progress towards the development of molecular diagnostic tools. This review provides a brief account of the techniques traditionally used for detection and describes developments in molecular-based methods for the detection and surveillance of marine pest species. Recent advances provide a platform for the development of practical, specific, sensitive and rapid diagnosis and surveillance tools for marine pests for use in effective prevention and control strategies.     

基因芯片技术在病原细菌检测中的应用

基因芯片技术具有快速、高通量、平行化等优点,在病原细菌检测中有广泛的应用前景,选择细菌适宜的靶基因是芯片制备的关键之一。用细菌核糖体基因做靶基因的芯片技术,虽然应用广泛,但仍存在一些不足,随着基因组信息及基因功能的深入研究,包括毒力基因、耐药基因等具有较好种属特异性的细菌基因不断被发现,为芯片技术检测病原细菌提供了更多特异的靶基因,使检测结果更加灵敏、准确,在病原细菌研究中将发挥更大的作用。     

Production and partial purification of invertase using <Emphasis Type="Italic">Cympopogan caecius</Emphasis> leaf powder as substrate

The present study investigates the efficiency of Aspergillus niger to produce invertase, an industrially important enzyme by using powdered stem of Cympopogan caecius (Lemon grass) as sole substrate and sole carbon source for the microorganism. The molecular weight of invertase was estimated to be 66–70 kDa by sodium do decyl sulphate poly acrylamide gel electrophoresis (SDS PAGE). The production of the enzyme was studied at different pH scales ranging from pH 4.0 to 7.0 at a constant temperature of 30°C and 2% substrate concentration. The maximum production of invertase (specific activity −0.0516 μk/mg protein) was obtained at pH 5.5 at 30°C temperature, and incubation for 48 h. The activity was found to be stable at pH 5.5 for 30 min. The enzyme was found to be stable in the temperature range of 20–55°C. The effect of divalent metal ions Cu²⁺, Fe²⁺, Co²⁺ on the activity of the enzyme invertase showed that these ions affected the activity by a certain factor. The study can be further industrially exploited in a country-like India where lemon grass is found in plenty and can be used as substrate for enzyme production. Moreover, the preparation of the substrate is also a simple process.     

石豆兰属(Bulbophyllum)(兰科)中两个种的新名称

本文发表石豆兰属Bulbophyllum（Orchidaceae）中两个种的新名称：Bulbophyllum maanshanense和Bulbophyllum xiajinchuangense以取代两个应废弃的晚出同名：Bulbophyllum malipoense Z.J.Liu,L.J.Chen＆W.H.Rao（2010）,non Z.J.Liu,S.C.Chen＆S.P.Lei（2008）和Bulbophyllum minus Z.J.Liu,L.J.Chen＆W.H.Rao（2010）＂minor＂,non（De Wild.）De Wild.（1921）。     

A Bayesian method to estimate the optimal threshold of a longitudinal biomarker

The objective of this study was to develop methods to estimate the optimal threshold of a longitudinal biomarker and its credible interval when the diagnostic test is based on a criterion that reflects a dynamic progression of that biomarker. Two methods are proposed: one parametric and one non‐parametric. In both the cases, the Bayesian inference was used to derive the posterior distribution of the optimal threshold from which an estimate and a credible interval could be obtained. A numerical study shows that the bias of the parametric method is low and the coverage probability of the credible interval close to the nominal value, with a small coverage asymmetry in some cases. This is also true for the non‐parametric method in case of large sample sizes. Both the methods were applied to estimate the optimal prostate‐specific antigen nadir value to diagnose prostate cancer recurrence after a high‐intensity focused ultrasound treatment. The parametric method can also be applied to non‐longitudinal biomarkers.     

Functional expression of human pyruvate carboxylase for reduced lactic acid formation of Chinese hamster ovary cells (DG44)

To investigate the effect of human pyruvate carboxylase (hPC) on lactate formation in Chinese hamster ovary (CHO) cell lines, FLAG-tagged hPC was introduced into a dihydrofolate-deficient CHO cell line (DG44). Three clones expressing high levels of hPC, determined by Western blotting using an anti-FLAG monoclonal antibody, and a control cell line were established. Immunocytochemistry revealed that a substantial amount of expressed hPC protein was localized in the mitochondria of the cells. hPC expression did not impair cell proliferation. Rather, it improved cell viability at the end of adherent batch cultures with the serum-containing medium probably because of reduced lactate formation. Compared with control cells, specific lactate production rate of the three clones was decreased by 21–39%, which was because of a decreased specific glucose uptake rate and yield of lactate from glucose. Reduced lactate formation by hPC expression was also observed in suspension fed-batch cultures using a serum-free medium. Taken together, these results demonstrate that through the expression of the hPC enzyme, lactate formation in CHO cell culture can be efficiently reduced.     

雌核发育银鲫子代中微卫星特异序列分析

雌核发育个体的基因型基本上完全与母本相同,这是源于卵子发生过程中没有经过减数分裂.父本的遗传物质是在随机水平、亚基因组水平或基因组水平参与到子代的遗传重组过程,从而对长期突变积累的雌核发育生物基因组进行补偿,一直是遗传学家关注的问题.本文对雌核发育银鲫特异个体及父母本5个微卫星位点的扩增条带进行了克隆测序,相似性比对结果显示,特异个体所表现的父咎匾霥NA条带,序列结果与父本完全相同或相似(SCM4、SCM9、YJ5),并在某些位点上保留了母本的特异条带(YJ5),而个体本身特异的DNA条带与父母本的相似性均较高(SCM13).同时,所检测到的个体经越冬后查验为雌性个体,进一步进行同源繁育,研究变异条带在繁殖中的命运.连续2代的繁育检测结果表明,融合了父本特异性条带的银鲫个体在繁殖过程中仍行雌核发育的生殖方式,变异来的条带能够传递给子代,进一步证实同源雌核发育银鲫通过小概率两性融合事件丰富银鲫种群的遗传多样性[动物学报 53(3):537-544,2007].     

Local spin dynamics in magnetic molecular chains studied by NMR and μSR

We present NMR and μ⁺SR study of spin dynamics in one-dimensional and quasi-one-dimensional molecular magnets of recent synthesis. In particular, we focus on the so called Gd(hfac)₃NIT-R and CoPhOMe magnetic chains families. For Gd-R helimagnets we show some differences between “weakly frustrated systems” and “fully frustrated systems”. The different behaviour is due to the different radical inserted in the chains (R = Me, Ph for “weakly frustrated systems” and R = iPr, Et for “fully frustrated systems”). The existence of different phase transitions, particularly to 3D long-range magnetic order in Gd-Ph and to chiral order in Gd-iPr, is remarked together with a comparison between results obtained from macroscopic and microscopic investigating techniques. As regards CoPhOMe slowly relaxing chain, the ¹H NMR measurements confirm the freezing of the spins at low temperature, which prevents the 3D long-range order, and display the presence of two relaxation mechanisms related to distinct contributions to the local spin relaxation.     

Stimulation,Inhibition, or Stabilization of Na,K-ATPase Caused by Specific Lipid Interactions at Distinct Sites

The activity of membrane proteins such as Na,K-ATPase depends strongly on the surrounding lipid environment. Interactions can be annular, depending on the physical properties of the membrane, or specific with lipids bound in pockets between transmembrane domains. This paper describes three specific lipid-protein interactions using purified recombinant Na,K-ATPase. (a) Thermal stability of the Na,K-ATPase depends crucially on a specific interaction with 18:0/18:1 phosphatidylserine (1-stearoyl-2-oleoyl-sn-glycero-3-phospho-l-serine; SOPS) and cholesterol, which strongly amplifies stabilization. We show here that cholesterol associates with SOPS, FXYD1, and the α subunit between trans-membrane segments αTM8 and -10 to stabilize the protein. (b) Polyunsaturated neutral lipids stimulate Na,K-ATPase turnover by >60%. A screen of the lipid specificity showed that 18:0/20:4 and 18:0/22:6 phosphatidylethanolamine (PE) are the optimal phospholipids for this effect. (c) Saturated phosphatidylcholine and sphingomyelin, but not saturated phosphatidylserine or PE, inhibit Na,K-ATPase activity by 70–80%. This effect depends strongly on the presence of cholesterol. Analysis of the Na,K-ATPase activity and E₁-E₂ conformational transitions reveals the kinetic mechanisms of these effects. Both stimulatory and inhibitory lipids poise the conformational equilibrium toward E₂, but their detailed mechanisms of action are different. PE accelerates the rate of E₁ → E₂P but does not affect E₂(2K)ATP → E₁3NaATP, whereas sphingomyelin inhibits the rate of E₂(2K)ATP → E₁3NaATP, with very little effect on E₁ → E₂P. We discuss these lipid effects in relation to recent crystal structures of Na,K-ATPase and propose that there are three separate sites for the specific lipid interactions, with potential physiological roles to regulate activity and stability of the pump.