SDS-PAGE analysis of whole cell protein and outer memrbane protein patterns of clinical isolates of Burkholderia pseudomallei

Objective:To investigate the banding patterns of whole cell protein(WCP) and outer membrane protein (OMP) of Burkholderia pseudomallei(B.pseudomallei) in clinical isolates from patients with melioidosis. Methods:WCP and OMP of of B.pseudomallei in 50 clinical isolates,from 47 patients with melioidosis were prepared and separated by polyacrylamide gel electrophoresis(SDS-PAGE) using 10%gels and stained with Coomassie brilliant blue.The banding patterns were compared by using a laser densitometer and dendrogram. Results:There were 6 different banding patterns of WCP and 2 types of OMP.Type 1 -5 WCP had 8 common protein bands at 19.0 - 45.0 kDa with identical OMP pattern.The banding patterns of WCP in type 6 were distinct from the others and also its OMP profile.The majority of clinical isolates(37/50,74%) were in type 1 WCP.Of the remaining isolates,8 were in type 2,2 in type 3,and one each was in type 4 to 6.There was no significant association between the WCP typing and the demographic or clinical features of the investigated patients.Conclusion:Despite the wide variation of clinical features of melioidosis,the results of this study show that B.pseudomallei had a few differences in the WCP and OMP profiles.Therefore typing of WCP and OMP,using SDS-PAGE analysis,could be an alternative method for phenotypic differentiation in clinical isolates of B.pseudomallei.

Significantly improved oxidation of bio-based furans into furan carboxylic acids using substrate-adapted whole cells

Furan carboxylic acids are important building blocks in polymer and fine chemical industries. In this work, a simple substrate adaptation strategy was applied to improve the catalytic performances of Comamonas testosteroni SC1588 cells for the synthesis of various furan carboxylic acids. It was found that biocatalytic synthesis of 5-hydroxymethyl-2-furancarboxylic acid(HMFCA) was substantially promoted by adding histidine and increasing cell concentrations. HMFCA was produced in a quantitative yield from200 m M HMF in 24 h. Besides, the HMFCA yields of 71%–81% were achieved with the substrate concentrations up to 250–300 m M. It was firstly found that 4-tert-butylcatechol(TBC), as the stabilizer present in HMF, exerted a significantly detrimental effect on whole-cell catalytic synthesis of HMFCA at high substrate concentrations(more than 130 m M). In addition, a variety of furan carboxylic acids such as2-furoic acid, 5-methyl-2-furancarboxylic acid and 5-methoxymethyl-2-furancarboxylic acid were synthesized with the yields up to 98%.

Acaricidal activities of whole cell suspension,cell-free supernatant,and crude cell extract of Xenorhabdus stokiae against mushroom mite (Luciaphorus sp.)

Xenorhabdus bacterium has been used as a biological control agent against Luciaphorus sp.,a mushroom mite endemic in Thailand.To develop an effective formulation of Xenorhabdus stokiae,treatments using different parts of X.stokiae isolate PB09 culture,including whole cell suspension,cell-free supernatant,and crude cell extract,were performed.The results show that different parts of X.stokiae isolate PB09 culture could induce variable effects on mite mortality and fecundity.Application with cell-free supernatant of X.stokiae culture resulted in both the highest mite mortality rate [(89.00±3.60)%] and the lowest mite fecundity [(41.33±23.69) eggs/gravid female].Whole cell suspen-sion of X.stokiae isolate PB09 culture was found to be slightly less effective than its cell-free supernatant,suggesting that X.stokiae was more likely to release its metabolites with acaricidal activities to the surrounding culture media.Crude cell extract of X.stokiae was not effective against mites.Cell-free supernatant of X.stokiae isolate PB09 was the most effective biological control agent and it could be conveniently used in future formulations instead of live bacteria.

Suppression of transmembrane sodium currents on the freshly isolated hippocampal neuron cell with continuous infrared light

Physiotherapeutic effects of infrared lasers have been proved in clinic.These infrared-based regulations of the bioelectrical activities can roughly be classied into enhancement and suppression of action potential(AP),which are described by sodium(Na)and potassium(K)transmembrane current equations,named as Hodgkin and Huxley(HH)-model.The enhancement effect is able to evoke or strengthen the AP when infrared light is applied.Its corresponding mechanism is commonly ascribed to the changes of the cell membrane capacitance,which is transiently increased in response to the infrared radiation.The distinctive feature of the suppression effect is to inhibit or reduce the AP by the designed protocols of infrared radiation.However,its mechanism presents more complexity than that in enhancement cases.HH-model describes how the Na current determines the initial phase of AP.So,the enhancement and suppression of AP can be also ascribed to the regulations of the corresponding Na currents.Here,a continuous infrared light at the wavelength of 980 nm(CIS-980)was employed to stimulate a freshly isolated hippocampal neuron in vitro and a suppression effect on the Na currents of the neuron cell was observed.Both Na and K currents,which are named as whole cell currents,were simultaneously recorded with the cell membrane capacitance current by using a patch clamp combined with infrared irradiation.The results demonstrated that the CIS-980 was able to reversibly increase the capacitance currents,completely suppressed Na currents,but little changed K currents,which forms the steady outward whole cell currents and plays a major role on the AP repolarization.A conrmation experiment was designed and carried out by synchronizing tens of milliseconds of infrared stimulation on the same kinds of hippocampal neuron cells.After the blocked K channel,a reduction of Na current amplitude was still recorded.This proved that infrared suppression of Na current was irrelevant to K channel.A membrane capacitance mediation process was preliminarily proposed to explain the Na channel suppression process.

Whole-cell recordings of calcium and potassium currents in acutely isolated smooth muscle cells

瞄准：在 mes 伤寒的尖锐地孤立的平滑肌房间记录钙和钾水流在老鼠的动脉的分支。方法：平滑肌房间被胶原酶文摘和机械研碎刚与擦亮的吸量管孤立。在整个房间的模式的补丁 clamp 技术被采用记录钙和钾水流。结果：过程分裂了没有损害电镀物品的平滑肌房间房间的生理的特征。电压门 Ca2+ 和钾水流成功地用整个房间的补丁 clamp 配置被记录。结论：方法分裂从老鼠 mes 伤寒的平滑肌房间动脉的分支。电压门隧道水流能在这准备被记录。

Whole-cell recording of the robust nucleus of the arcopallium neurons in the adult zebra finch

BACKGROUND： Electrophysiological properties of the song nucleus have been revealed using conventional techniques, such as intracellular and extracellular recording. Research concerning the neuronal activation properties and regulations of the song system at the cellular and ion channel level may help reveal the neural mechanism of song learning. OBJECTIVE： To perform whole-cell recording of robust nucleus of the arcopallium （RA） neurons in brain slices from adult zebra finches （Taeniopygia guttata） and observe the action potential, sodium/potassium current and the spontaneous postsynaptic current of RA neurons. DESIGN, TIME AND SETTING： Self-controlled, neuroelectrophysiological experiment. The study was performed at the Neurophysiology Laboratory of South China Normal University from April to September 2008. MATERIALS： Flaming/Brown puller P-97 was purchased from Sutter Ins, USA; Axopatch 700B amplifier and Digidata 1332A converter were purchased from Axon Instrument, USA; pClamp software was provided by Axon Instrument, USA. METHODS： RA neurons were acutely isolated from 24 healthy male zebra finches. The action potential, voltage-gate sodium/potassium current and spontaneous postsynaptic current were recorded by whole-cell recording technology. Data were analyzed by pClamp software. MAIN OUTCOME MEASURES： The amplitude and frequency of the action potential, and the amplitude of the voltage-dependent and spontaneous postsynaptic currents, were measured. RESULTS： （1） Testing of action potential： Cells exhibited a stable current-voltage relationship following a series of hyperpolarization stepped currents, and an action potential was triggered by the spike threshold. All the recorded cells displayed repetitive firing following depolarizing current injection, with a frequency beyond 100 Hz. （2） Testing of voltage-gate currents： The inward and outward whole-cell currents were observed after a series of depolarizing voltage steps. The inward current disappeared following the application of tetrodotoxin and the outward current was significantly inhibited by application of 4-aminopyfidione and tetraethylammonium chloride. （3） Testing of spontaneous postsynaptic current： The majority of recorded cells exhibited an inward synaptic current when the membrane potential was maintained at -60 mV, with some cells exhibiting a robustly outward current when the membrane potential was maintained at -30 mV. Tetrodotoxin was unable to affect the spontaneous postsynaptic current. Following application of bicuculline [y-aminobutyric acid （A） receptor antagonist] and high concentration kynurenic acid （ionotropic glutamate receptor antagonist）, the inward and outward currents were completely inhibited. CONCLUSION： Under these experimental conditions, the action potential, sodium/potassium current and spontaneous postsynaptic current were recorded successfully in RA neurons. This indicates that the cells preserved relatively intact synaptic connections and normal physiological activity, which is required for investigating ion channels. The inward and outward whole-cell currents were sodium and potassium currents, respectively. The postsynaptic y-aminobutyric acid （A） receptors and ionotropic glutamate receptors contributed to the spontaneous postsynaptic current.

Effect of Cu^2＋ on K^＋ Current in Acutely Isolated Rat Hippocampal Neurons by Whole Cell Patch Clamp Technique

用整个房间补丁夹钳技术，短暂的外面的 K+ 电流(Ito ) 和推迟的整流器 K+ 电流(Idr ) 上的 Cu2+ 的效果在尖锐地孤立的老鼠被学习海马趾的神经原。当 Cu2+was 的集中比 2H 降低时， Ito 和 Idr

Whole-cell recordings of voltage-gated Calcium,Potassium and Sodium currents in acutely isolated hippocampal pyramidal neurons

Objective：To record Calcium, Potassium and Sodium currents in acutely isolated hippocampal pyramidal neurons. Methods：Hippocampal CA3 neurons were freshly isolated by 1 mg protease/3 ml SES and mechanical trituration with polished pipettes of progressively smaller tip diameters. Patch clamp technique in whole-cell mode was employed to record voltage-gated channel currents. Results：The procedure dissociated hippocampal neurons, preserving apical dendrites and several basal dendrites, without impairing the electrical characteristics of the neurons. Whole-cell patch clamp configuration was successfully used to record voltage-gated Ca^2＋ currents, delayed rectifier K^＋ current and voltage-gated Na^＋ currents. Conclusion：Protease combined with mechanical trituration may be used for the dissociation of neurons from rat hippocampus. Voltage-gated channels currents could be recorded using a patch clamp technique.

Incorporation of circulating tumor cells and whole-body metabolic tumor volume of 18F-FDG PET/CT improves prediction of outcome inⅢB stage small-cell lung cancer

Objective: We investigated the correlation between the number of circulating tumor cells(CTCs) and wholebody metabolic tumor volume(WBMTV) measured by 18 F-fluorodeoxyglucose(FDG) positron emission tomography/computed tomography(PET/CT).The aim was to evaluate the value of the incorporation of CTC number and WBMTV in the prognostic prediction of stage III small-cell lung cancer(SCLC).Methods: One hundred and twenty-nine patients were enrolled in this study.All patients were treated with four cycles of a platinum-based regimen and concurrent chest irradiation,followed by prophylactic cranial irradiation.Blood samples for CTC analysis were obtained from 112 patients before the initiation of chemotherapy(as a baseline),after cycle 1 and after cycle 4.CTCs were measured using the CELLSEARCH? system.The patients underwent pretreatment FDG PET/CT WBMTV,which included all malignant lesions.The Spearman rank test was used to determine the correlation among CTC counts,WBMTV and disease stage.Overall survival(OS) and progression-free survival(PFS) curves were produced using the Kaplan-Meier method,and survival differences between groups were assessed by the log-rank test.Results: The number of CTCs at baseline did not correlate with WBMTV before the initiation of therapy(P=0.241).The number of CTCs at baseline and the WBMTV before the initiation of therapy were independent relevant factors for PFS and OS.The subgroup analysis(Group A: CTC count >19.5 and a WBMTV >266.5cm~3;Group B: CTC count >19.5 and a WBMTV ≤266.5cm~3; Group C: CTC count ≤19.5 and a WBMTV >266.5cm~3;Group D: CTC count ≤19.5 and a WBMTV ≤266.5cm~3) showed that the differences were statistically significant in the median PFS(Group A vs.D,P<0.001; Group B vs.D,P=0.018; Group C vs.D,P=0.029) and in the median OS(Group A vs.D,P<0.001; Group B vs.D,P=0.012).Conclusions: CTC number and WBMTV are related to progression and death in patients with SCLC.The incorporation of CTC number and WBMTV scans can provide a detailed prognostic prediction for SCLC.

Gene expression in rat mesenchymal stem cells following treatment with natural cerebrolysin-containing serum Validation of a whole genome microarray technique

BACKGROUND： Natural cerebrolysin （NC）, a Chinese herbal drug for the treatment of Alzheimer＇s disease （AD）, induces mesenchymal stem cell （MSC） differentiation into neuron-like cells, with low toxicity. But the mechanisms involved in NC effects on MSCs remain poorly understood. OBJECTIVE： We used a whole genome microarray technique to further investigate the molecular, genetic, and pharmacodynamic mechanisms of NC on MSC gene expression profiles. DESIGN, TIME AND SETTING： A parallel, controlled, in vitro experiment was performed at the First Affiliated Hospital of Shenzhen University, Shenzhen Institute of Integrated Chinese and Western Medicine, China, between September 2006 and October 2008. MATERIALS： NC was provided by Shenzhen Institute of Integrated Chinese and Western Medicine China. It was predominantly composed of Renshen （Radix Ginseng）, Tianma （Rhizoma Gastrodiae） and Yinxingye （Ginkgo Leaf） and prepared by conventional water extractJon technology. Twelve adult, male, New Zealand rabbits were included, six of which underwent intragastric administration of NC extract for 1 month to create NC-containing serum. METHODS： Bone marrow was collected from the tibia and femur of Sprague Dawley rats, aged 6 8 months old. Rat MSCs were isolated and purified by the whole bone marrow adherence method. After in vitro culture, MSCs from passage 4 were treated with NC-containing serum for 48 hours, and total RNA was extracted. Gene expression in MSCs was analyzed using Affymetrix whole genome microarray analysis. MAIN OUTCOME MEASURES： Differentially expressed genes in NC serum-treated MSCs. RESULTS： NC treated MSCs displayed 46 differentially expressed genes, 22 with upregulated expression （fold change 〉 2） and 24 with downregulated expression （fold change 〈 -2）. Differentially expressed genes participated in neuronal growth, differentiation, and function, cell growth, differentiation, proliferation, apoptosis, signal transduction, substance/energy metabolism, ion transport, and immune responses. NC treatment changed levels of transforming growth factor β/ bone morphogenetic proteins, Hedgehog, Bmp, and Wntsignaling pathways, which regulate nerve cell differentiation, development and function, as well as learning and memory; Ras, G protein- coupled receptor signal pathways that are related to cell growth, proliferation, and apoptosis; and mitogen-activated protein kinase kinase kinase signaling cascades. CONCLUSION： NC can regulate gene expression for many signal transduction pathways related to nerve cell differentiation, development and function, learning and memory function, as well as regulation of cell growth, differentiation, proliferation, or apoptosis to mediate the genetic effects of NC treatment on AD.

小白链霉菌全细胞转化L-赖氨酸合成ε-聚赖氨酸的体系构建与优化

小白链霉菌(Streptomyces albulus)是天然抗菌肽ε-聚赖氨酸(ε-poly-L-lysine,ε-PL)的主要生产菌株。为了提高小白链霉菌生产ε-PL效率,该文构建并优化了全细胞转化L-赖氨酸合成ε-PL体系:葡萄糖质量浓度80 g/L,菌龄12 h,反应温度30℃,L-赖氨酸质量浓度15 g/L,柠檬酸浓度15 g/L,初始反应p H 4.0,硫酸铵质量浓度6 g/L,湿菌体量为1900 g/L。基于该转化体系,实现小白链霉菌在96 h合成ε-PL产量和底物转化率达到13.80 g/L和38.9%,分别是常规摇瓶发酵的4.1、3.2倍。最后,在小白链霉菌中异源表达来自大肠杆菌的L-赖氨酸特异性通透蛋白基因lysp,获得的重组菌S.albulus OE-lysp实现L-赖氨酸利用能力和底物转化率较出发菌株分别提升26%和33%,ε-PL产量增加至17.21 g/L,约为常规摇瓶发酵ε-PL产量的6.4倍,这是文献报道的最高摇瓶规模ε-PL产量。该研究结果一方面说明了通过全细胞转化L-赖氨酸生产ε-PL的可行性,另一方面为S.albulus转化大宗氨基酸L-赖氨酸生产高值ε-PL奠定了坚实的技术基础,具有重要的理论意义和经济价值。

重组大肠杆菌全细胞催化法生产N-乙酰神经氨酸

N-乙酰神经氨酸具有多种生物学功能,在食品添加剂和药物合成等方面有着重要的应用。为了降低成本,作者利用重组大肠杆菌,并以含有N-乙酰葡萄糖胺的发酵液为底物进行全细胞催化生产N-乙酰神经氨酸。结果表明,在温度为30℃、转化液初始pH为6.5、底物丙酮酸浓度为1.38 mol/L、Triton X-100添加质量分数为0.4%、菌体OD_(600)为30的条件下在5 L发酵罐等条件下进行全细胞转化,可以得到N-乙酰神经氨酸180 mmol/L,摩尔转化率为65.45%。用阴离子树脂对产物进行初步分离纯化,经高效液相色谱分析证实纯化后产品为高纯度N-乙酰神经氨酸,其纯度为98.3%,结晶回收率为42.5%。作者建立并优化了一种以含有N-乙酰葡萄糖胺的发酵液为底物直接进行全细胞催化生产N-乙酰神经氨酸的工艺流程,既节约了成本,又具有可持续发展的优势。

基于细菌双组分系统的生物传感器的研究进展

细菌双组分系统能够感知和响应细胞内外的物理、化学和生物刺激,通过耦合传感和调节机制从而引起一系列的细胞反应,是一个普遍存在的信号转导通路家族。当前越来越多的合成生物学家已开始利用双组分系统的特异属性来工程化设计微生物传感系统,并应用于光遗传学、材料科学、肠道微生物组工程、生物炼制和土壤改良等领域。本综述重点介绍了开发基于双组分系统的生物传感器的最新研究进展以及在各个领域中的潜在应用。同时探讨了如何运用新的工程方法提高双组分系统传感器性能的可靠性,包括遗传重构、DNA结合结构域交换、检测阈值调节和磷酸化串扰隔离,以及如何根据特定应用的要求定制双组分系统信号特性。在未来,研究者可以将这些方法与大规模的基因合成、高通量筛选相结合,以加速和帮助发现更多未确定特征输入的双组分系统,并开发新的对广泛的刺激做出反应的基因编码生物传感器,拓展双组分生物传感器在不同领域的应用。

镉全细胞微生物传感器研究进展

镉全细胞微生物传感器(cadmium whole-cell biosensors,Cd-WCBs)以微生物为载体,利用微生物的调节元件组成模块化基因回路,以实现镉生物有效性的简单、经济和高通量检测.本文概述了基于转录因子和酶生物传感器构建的非特异性Cd-WCBs,以及基于转录因子和荧光共振能量转移构建的特异性Cd-WCBs.本文还总结了Cd-WCBs的基本优化策略,主要包括对识别蛋白进行定向改造或定向进化、利用反馈调控优化基因回路以及改造底盘细胞的金属调控系统.目前,Cd-WCBs已经用于不同环境介质中镉的生物有效性检测,但是其在实际环境中细胞活性,和检测性能仍有待提高.本研究指出未来可通过开发和改造底盘生物来提高传感器的环境适应能力,利用多种合成生物学手段进一步提高传感器的检测灵敏度和特异性.

重组大肠杆菌全细胞催化合成D-甘油醛

D-甘油醛在医药、农业化学品和天然产物合成中发挥着重要作用。通过改造天蓝色链霉菌糖醇氧化酶基因,在大肠杆菌Rosetta(DE3)菌株中进行重组表达,采用全细胞催化方法将甘油转化成D-甘油醛,与传统方法相比该方法具有绿色、安全、高效的特点。对影响蛋白表达的诱导条件进行单因素优化;并对影响全细胞催化的反应条件进行了研究。结果表明,诱导剂IPTG 0.2 mmol/L、诱导温度28℃、诱导时间6 h时,构建的大肠杆菌pET-28a(+)-aldO工程菌的相对酶活性最高;菌体光密度(OD600)为10、缓冲液pH 7.5、反应温度30℃、反应时间60 min时,甘油的转化率可以达到46%,为D-甘油醛的生物合成奠定了基础。

一锅法全细胞催化合成胞苷三磷酸的研究

分别在大肠杆菌BL21(DE3)中构建胞苷激酶(CDK)与乙酸激酶(ACK)的共表达及融合表达体系和胞苷酸激酶(CMK)与乙酸激酶(ACK)的融合表达体系,其中融合菌株SUMO-CDK-L2-ACK与CMK-L2-ACK构成的双融合催化体系具有较好的催化活性。搭建了双融合菌全细胞一锅法催化合成胞苷三磷酸(CTP)反应体系,并对其温度、pH、金属离子、乙酰磷酸投加量及菌粉投加量等进行优化。结果表明,在优化反应体系中,反应75 min时CTP产量达到最高为108 mmol/L,总收率达86.4%,实现了CTP的一锅法高效合成。

Xanthomonas maltophilia转化制备熊去氧胆酸及中间产物

以野生型嗜麦芽黄单胞菌(Xanthomonas maltophilia)为出发菌株,鹅去氧胆酸/β-环糊精包合物为反应底物,利用嗜麦芽黄单胞菌在液体发酵过程中产生的7α-羟基类固醇脱氢酶和7β-羟基类固醇脱氢酶,全细胞酶法催化制备熊去氧胆酸及中间产物。对嗜麦芽黄单胞菌形态鉴定,酶活测定并优化,制定产物检测方法。表明嗜麦芽黄单胞菌为杆状、单鞭毛、革兰氏阴性菌。菌株破碎后,SDS-PAGE分析表明在26-33 kDa之间存在蛋白条带,测定7α-羟基类固醇脱氢酶和7β-羟基类固醇脱氢酶酶活分别为79 U/mL、35 U/mL;优化显示,温度为35°C、pH值为9.0、添加30%甲醇时酶的活性提升;转化后UDCA得率为17.2 mg/L,7K-LCA得率为18.2 mg/L。作为一种野生型的底盘转化菌种,该研究为全细胞催化制备熊去氧胆酸及其中间产物提供了新的途径。

生物法合成熊去氧胆酸研究进展

熊去氧胆酸(UDCA)是治疗肝胆疾病的基础性药物,对某些癌症和神经系统疾病也有辅助治疗作用。化学工艺合成UDCA对环境不友好、收率低,尚不能满足生产需求;生物法合成UDCA具有转化率高、节省能源、对环境友好的特点,目前是UDCA合成的研究发展方向。生物法合成是以廉价易得的鹅去氧胆酸(CDCA)、胆酸(CA)或石胆酸(LCA)为底物,通过7α-HSDH、7β-HSDH、LDH和GDH四种酶催化合成UDCA,合成方法分为游离酶催化和全细胞合成,其中游离酶催化常采用“一锅两步法”或“一锅一步法”合成UDCA;全细胞催化是以构建的工程细胞作为反应容器,利用细胞表达的酶系催化合成UDCA。本文综述了游离酶催化和全细胞合成UDCA的相关用酶、合成方式及合成工艺的研究进展,为UDCA的研究生产提供技术参考。

基于全细胞生物传感器的污染物生物有效性评估研究进展

环境污染是威胁生态系统和人类健康的重要问题。环境中污染物的检测和风险评估对于确定环境污染治理方案至关重要。全细胞生物传感器为环境中污染物的风险评估提供了一种灵活、快速且经济、有效的方法,其在检测多种污染物的生物有效性方面表现出了卓越的能力。全细胞生物传感器的性能主要取决于其构建因素,如调控基因、报告基因和宿主菌株;同时,试验条件也会对其性能产生较大影响。本文通过介绍全细胞生物传感器的分类及工作原理,并综述利用全细胞生物传感器评估环境中重金属和有机污染物生物有效性的研究进展,为相关领域的研究提供参考。

Toxicity assessment of heavy metals and organic compounds using CellSense biosensor with E.coli

A new strategy using an arnperometric biosensor with Escherichia coli （E. coli） that provides a rapid toxicity determination of chemical compounds is described. The CellSense biosensor system comprises a biological component immobilized in intimate contact with a transducer which converts the biochemical signal into a quantifiable electrical signal. Toxicity assessment of heavy metals using E.coli biosensors could be finished within 30 min and the 50% effective concentrations （ECso） values of four heavy metals were determined. The results shows that inhibitory effects of four heavy metals to E.coli can be ranked in a decreasing order of Hg^2＋ 〉 Cu^2＋ 〉 Zn^2＋ 〉 Ni^2＋, which accords to the results of conventional bacterial counting method. The toxicity test of organic compounds by using CellSense biosensor was also demonstrated. The CellSense biosensor with E. coli shows a good, reproducible behavior and can be used for reproducible measurements.