Photocatalytic degradation of trace-level of MicrocystinLR by nano-film of titanium dioxide

The occurrence of toxic water bloom of cyanobacte-ria algae, widely reported in eutrophic freshwater, hasbeen a serious pollution problem in recent years[1]. Mi-crocystins (MCs), the most common cyanobacteriatoxin with a cyclic heptapeptide structure (Fig…     

Preconcentration of vanadium(V) on crosslinked chitosan and determination by graphite furnace atomic absorption spectrometry

A new method is proposed for the preconcentration of vanadium(V) with crosslinked chitosan (CCTS) and determination by graphite furnace atomic absorption spectrometry (GFAAS). The adsorption rate of vanadium(V) by CCTS was 97% at pH 4.0, and vanadium(V) was eluted from crosslinked chitosan with 2 mL 2.0 mol·L⁻¹ chlorhydric acid and determined by GFAAS. The detection limit (3σ,n=7) for vanadium (V) was 4.8×10⁻¹²g and the relative standard deviation (R.S.D) at concentration level of 2.6 μg·L⁻¹ is less than 3.6%. The method shows a good selectivity and high sensity, and it was applied to determination of vanadium(V) in oyster and water samples. The analytic recoveries are (97±5)%. Biography: Wu Wei (1975-), female, Master candidate, research direction: environmental & analytical chemistry.     

Effect of Nano red elemental selenium on GPx activity of broiler chick kidney cells<Emphasis Type="Italic">in vitro</Emphasis>

A new selenium source, Nano red elemental selenium (Nano-Se) was used to study the effect on the GPx activity of broiler chick kidney cells (BCKC)in vitro, Sodium selenite (Na₂SeO₃) and seleno-1-methionine (Se-Met) were used as the controls. The results showed that the effects of three kinds of Se forms on the GPx activity of BCKC were accordant (p>0.05) compared with each other at 0.01. 0.05 and 0.10 μmol/L Se concentrations treatments. In the range of 0.00–0.10 μmol/L Se concentrations, the GPx activity increased with elevation of Se concentrations in medium. For the three kinds of Se forms, the GPx activity reached the climax at 0.10 μmol/L Se concentration. At 0.20 and 0.30 μmol/L Se concentrations, the influnces of three kinds of Se forms were not accordant with one another. For Nano-Se, the GPx activity at 0.20 and 0.30 μmoi/L Se concentrations remained the same as that at 0.10 μmol/L Se concentration treatment. For Se-Met, the GPx activity at 0.20 μmol/L Se concentration treatment remained the same with 0.10 μmol/L treatment; the GPx activity at 0.30 μmol/L Se concentration treatment was declined significantly (p<0.05) compared with 0.10 or 0.20 μmol/L treatment. For Na₂SeO₃, the GPx activity falled gradually with Se concentration increasing from 0.10 μmol/L to 0.30 μmol/L, and at 0.30 μmol/L Se concentration treatment, the GPx activity was less than the original of BCKC. The results implicated, on the GPx activity of BCKCin vitro, the ranking of width range of the most suitable Se concentration for nutrition curve of the three Se formes is Nano-Se>Se-Met>Na₂SeO₃. Foundation item: Supported by the Key Item of the Science and Technology Bureau of Zhejiang Province (021122680) Biography: Xu Bao-hua (1966-), male, Associate professor, Ph. D. research direction: nanobiology and animal nutrition.     

Determination of sulfonamides with fluorescent inclusion complex of carbonic anhydrase and dansylamide

A new fluorimetric method for determination of sulfonamides was described based on the formation of a fluorescent inclusion complex of carbonic anhydrase(CA) with dansylamide(DNSA). The binding of DNSA to CA resulted in an enhancement in the fluorescence emission at 460 nm with excitation at 280 nm. Dissociation constants were determined for the carbonic anhydrase sulfonamide complexes. Linear calibration graphs of sulfonamides were obtained within a concentration range of 0- 0.058 μg/mL for DNSA; 0-0.344 μg/mL for sulfanilamide (SAN) and 0-0.286 μg/mL for P toluenesulfonamide (PTSN). The relative standard deviations were within 1.8%-4.2%. Limits of detection for DNSA, SAN and PTSN were 0.84, 19.5 and 6.1 ng/mL, respectively. The method was applied to the determination of sulfonamides in cow milk at ng/mL level.     

Spectrofluorimetric determination of tetracycline using Eu3+ chelation and cetyltrimethylammonium bromide

The fluorescence of tetracycline was greatly enhanced by chelation with Eu³⁺ in Tris-HCl buffer (pH8.5). The addition of cetyltrimethylammonium bromide, a cationic surfactant, further enhanced the fluorescence of tetracycline-Eu³⁺ chelates. This spectrofluorimetric method for the determination of tetracycline yielded a linear responses in the range of 10 nmol/L–10 μmol/L. The detection limit was 5 nmol/L (or 2.22 ng/mL). The recovery of tetracycline spiked in serum at levels of 1 and 0.09 μg/mL was 97.9% and 97.8%, respectively. This method is fast, sensitive and suitable for the determination of tetracycline in biological specimens. Foundation item: Supported by the National Natural Science Foundation of China Biography: Huang Zu-yun (1963-), male, Ph D.     

Microcalorimetric investigation of effect of berberine alkaloids from Coptis chinensis Franch on intestinal diagnostic flora growth

The inhibitory effect of three berberine alkaloids (BAs) from Coptis chinensis Franch, a traditional Chinese medicinal (TCM) herb, on Bifidobacterium adolescentis growth was investigated by microcalorimetry. The power-time curves of B. adolescentis with and without BAs were acquired, meanwhile the extent and duration of inhibitory effect on the metabolism were evaluated by the growth rate constant (k), half inhibitory ratio (IC₅₀), maximum heat-output power (P _max), peak time of maximum heat-output power (t _p) and total heat production (Q _t). k, P _max and Q _t decreased, and t _p was prolonged with the increase of BAs concentration. The IC₅₀ of BAs is 806 μg/mL for berberine, 341 μg/mL for coptisine and 236 μg/mL for palmatine. The sequence of antimicrobial activity of BAs is berberine < coptisine < palmatine. Combined with previous studies, it could be shown that the sequences of antimicrobial activity of BAs on both Bacillus shigae and Escherichia coli are berberine > coptisine > palmatine. The structure-function relationship of BAs indicates that the functional group methylenedioxy or methoxyl at C2 and C3 might be the major group inducing the activities of BAs on E. coli and B. adolescentis. Meanwhile, the substituent groups at C2, C3, C9 and C10 almost have equal effect on B. shigae. Supported by the National Natural Science Foundation of China (Grant Nos. 30625042 and 30873385) and Key Projects of National Science & Technology Pillar Program of China in the 11th Five-Year Period (Grant No. 2007BAI40B05)     

Cardiac protective role of a novel erythrocyte-derived depressing factor on rats and its Ca^2＋ mechanism

The cardiac protective role of a novel erythro-cyte-derived depressing factor (EDDF) on spontaneous hy-pertensive rats (SHR), calcium overload (CaO) rats and Wistar rats and its mechanism was evaluated. Mean artery pressure (MAP), heart rate (HR) and LVdp/dtmax were measured by physiological recorder. The effect of EDDF on the Ca2+-ATPase activity in myocardial sarcoplasmic reticu-lum (SR) of CaO rats was determined by inorganic phos-phate assay. Calcium transport in myocytes was measured by 45Ca2+ radioactive isotope measurement. The phosphoryla-tion levels of extracellular signal-regulated protein kinases (ERK1/2) in myocardial tissue of SHR and CaO rats were measured by Western blot method. And the ultrastructures of cardiac muscle cells were observed with the transmission electron microscope. The results indicated that EDDF could significantly decrease MAP, HR and LVdp/dtmax in a dose dependent manner (P < 0.05). It seems that the mechanism might relate with activating the Ca2+-APTase, enhancing the uptake and release of Ca2+ from SR (P < 0.05), decreasing the phosphorylation levels of ERK1/2 of myocytes (P < 0.01) and lightening the ultrastructural lesion of cardiac muscle cells. In CaO rats, the Ca2+-ATPase activity decreased clearly com-pared to control (64.99 7.16 vs 94.48 7.68 nmol·min-1 ·mg-1 protein, P < 0.01), while EDDF (100 mg/mL) could significantly increase the activity (87.93 ?9.54 vs 64.99 ?7.16, P < 0.05, n = 7). Both uptake and release rate of Ca2+ (祄ol 45Ca2+/g protein/min) from myocardial SR of CaO rats re-markably decreased compared to control (32.40 ?2.70 and 15.46 ?1.49 vs 61.09 ?10.89 and 25.47 ?4.29, P < 0.05); EDDF (100 mg/mL) could significantly stimulate their activi-ties (50.48 6.76 and 21.76 2.75 vs 32.40 2.70 and 15.46 1.49, P < 0.05). EDDF could evidently down-regulate the phosphorylation of ERK1/2 in myocardial tissue from SHR and CaO rats (P < 0.01), lighten the ultrastructural lesion of cardiac muscle cells of SHR as well. It is concluded that EDDF seems to play protective roles on both structure and function of heart, which closely related with amelioration of Ca2+ transport and inhibition of Ca2+-MAP kinase pathway.     

Application of Nanometer-Size Titanium Dioxide in Extreme-Trace V（Ⅴ） Analysis

0Introduction Vanadiumplaysanimportantroleinmodernindustry,es peciallyinsteelandchemicalindustry.Forinstance,itscompoundsarewidelyappliedintheproceduresofvitrioland petroleumchemicalmanufactureascatalyzers[14].Vanadium hasseveralvalences,butgenerallyitslowvalencesturnintohighoneseasilyinenvironment[5].BecauseV(Ⅴ)isthemost stableandpoisonousone,weoftenlayemphasisonitinenvi ronmentalpollutioncontrol.Vanadiumexistsinenvironmentalwaterwithextremelylowconcentration.Inseawateritscontentislessthan…     

Effect of Cl- on photosynthetic bicarbonate uptake in two cyanobacteria Microcystis aeruginosa and Synechocystis PCC6803

Photosynthetic inorganic carbon utilization was investigated in two cyanobacteria Microcystis aeruginosa and Synechocystis PCC6803 grown in standing culture. Photosynthetic rates for the two algae reached about 10 times the theoretical CO₂ supply rate at low dissolved inorganic carbon (DIC) of 100 μmol/L, and the rates were unaffected by the addition of 20 mmol/L Na⁺, indicating that the two algae possessed Na+-independent HCO^-₃ utilization for photosynthesis under low DIC. Their photo- synthetic rates at low DIC were inhibited by higher Cl^- and the degrees of inhibition were increased with the rise of CI^- concentration, and in the presence of Diphenylamine-2-carboxylate (DPC), a reported Cl^- channel inhibitor, the rates decreased by 74%－82%, implying that putative DPC-sensitive Cl^- channels participate in Na+-independent HCO₃^- uptake for photosynthesis. The experiment of intracellular 14C-DIC accumulation for photosynthesis showed that internal DIC pools decreased by about 80% with 200 μmol/L DPC and by 64%－70% with 100 mmol/L Cl^-. The experiment of chlorophyll a fluorescence quenching showed that initial rates and extents of fluorescence quenching obviously decreased with 200 μmol/L DPC or 100 mmol/L Cl^-. The two experiments gave further evidence that putative DPC-sen- sitive Cl^- channels participate in Na+-independent HCO^-₃ uptake for photosynthesis in the two algae grown in standing culture.     

Effect of CO<Subscript>2</Subscript> concentrations on the activity of photosynthetic CO<Subscript>2</Subscript> fixation and extracelluar carbonic anhydrase in the marine diatom <Emphasis Type="Italic">Skeletonema costatum</Emphasis>

The growth and activity of photosynthetic CO2 uptake and extracellular carbonic anhydrase (CAext) of the marine diatom Skeletonema costatum were investigated while cultured at different levels of CO2 in order to see its physio-logical response to different CO2 concentrations under either a low (30 靘ol·m-2·s-1) or high (210 靘ol·m-2·s-1) irradiance. The changes in CO2 concentrations (4—31 靘ol/L) affected the growth and net photosynthesis to a greater extent under the low than under the high light re-gime. CAext was detected in the cells grown at 4 mol/L CO2 but not at 31 and 12 靘ol/L CO2, with its activity being about 2.5-fold higher at the high than at the low irradiance. Photo- synthetic CO2 affinity (1/ K1/2(CO2)) of the cells de-creased with increased CO2 concentrations in culture. The cells cultured under the high-light show significantly higher photosynthetic CO2 affinity than those grown at the low-light level. It is concluded that the regulations of CAext activity and photosynthetic CO2 affinity are dependent not only on CO2 concentration but also on light availability, and that the de-velopment of higher CAext activity and CO2 affinity under higher light level could sufficiently support the photosyn-thetic demand for CO2 even at low level of CO2.     

半枝莲抗菌活性及其有效部位研究

目的研究半枝莲不同粗提物的体外抗菌活性,并初步确定其抗菌活性有效部位。方法采用甲醇冷浸法、乙醇热回流法及微波萃取法提取粗提物,96孔板培养法测定不同粗提物对的体外抑菌活性;将提取物分别用石油醚、乙酸乙酯和水萃取得到不同极性的萃取物组分,通过比较其抑菌活性初步确定半枝莲的抗菌有效部位。结果三种提取方法中,微波萃取法浸膏得出率最高;半枝莲的各粗提物对普通菌在2 mg/mL下未见抑制活性,但对耐甲氧西林金葡菌(ATCC33591和43300)半数抑制浓度(MIC值)达到2mg/mL;粗提物的萃取组分尤其是乙酸乙酯相,表现出广谱抗菌活性,其对各种菌株的半数抑制浓度大多在0.5～2 mg/mL范围,石油醚相对变异链球菌的抑菌活性较强,MIC值达到0.125 mg/mL。结论半枝莲具有广谱的抗菌活性,尤其是对耐药菌表现出较好的抗菌活性,并且初步确定抗菌有效部位为乙酸乙酯相,这为半枝莲抗菌应用的下一步研究奠定了基础。     

Fabrication of organically modified oxygen sensing film based on fluorescent quenching

An organically modified silicate (ORMOSIL) as a matrix for oxygen-sensitive sensor, in which di-methyldimethoxysilane was selected as an organic modifier in the precursor, is described. The sensing film with tris-(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) as an indicator developed in this paper was characterized by efficient quenching by oxygen. Blue light-emitting diodes (λmax = 475 nm) were employed as light excitation source. The linear range of the dissolved oxygen was from 0.5 to 16 μg/mL. The measured RSD was 2%, the response time (t95) was 60 s, and the determination limit was 0.2 μg/mL. A portable and inexpensive luminescence-based sensor was established and applied to the determina-tion of dissolved oxygen in the surface water.     

Investigation of hrDNA targeting vector-mediated tumor-specific suicide gene therapy for hepatocellular carcinoma

Vectors pose most pivotal problem of gene therapy[1]. Because of the high transfection efficiency both in vitro and in vivo, the viral vector has been employed in 70% clinical trials of gene therapy (http://www.wiley.co.uk/ genmed/clinical). However, thei…     

基于分子印迹膜的表面等离子体共振传感器检测黄体酮

分别采用热聚合和光聚合的方法在金膜表面合成黄体酮分子印迹膜,并将其作为识别元件应用于表面等离子体共振传感器检测黄体酮. 通过对其进行洗脱及吸附研究发现:采用乙腈/乙酸混合液可以快速将黄体酮洗脱下来,洗脱前后共振角分别移动了1.15°和0.72°;该传感器实现对黄体酮的最低检测限均为10-14 g/mL;在10-14～10-6 g/mL的浓度范围内,共振角度的变化与黄体酮浓度的负对数成线性关系. 同时将具有黄体酮识别位点的分子印迹膜分别吸附浓度为10-4 g/mL的雌二醇,睾酮和睾酮丙酸酯溶液,结果显示均没有非特异性吸附作用. 以上结果表明,基于黄体酮分子印迹膜的表面等离子体共振传感器能够对黄体酮实现快速定量的专一性检测.      

Effect of Quercetin on Breeding and Apoptosis of Cervical Cancer HeLa Cell and on Growth of Transplanted Tumor in Nude Mice

Effect of quercetin on HeLa cell system of cervical cancer was studied by methods of MTT and Annexin V-FITC/PI. The results show that quercetin has functions of inhibiting breeding of HeLa cells and inducing apoptosis of the cells. The total apoptosis rate is positively proportional to reaction duration and concentration of quercetin used. The maximum apoptosis rate being （88.76±2.35）% was obtained when the concentration was 50.0 μmol/L and the cells were treated with quercetin for 72 hours. Based on establishing a model of tumor of cervical cancer transplanted into nude mice, quercetin of different concentrations was injected into abdominal cavity of nude mice and situation of tumor growth was reviewed. The result showed that with quercetin concent＇ration increasing from 0 to 100.0 μmol/L, the transplantation volume and weight of the tumors decreased from （279.59±70.58） mm^3 and （0.145±0.019） g to （128.72±36.12） mm^3 and （0.089± 0.019） g respectively, while apoptosis rate of the transplanted tumor increased from （9.63±1.85）% to （34,98±0.47）%, which proved that quercetin inhibited increment of volume and weight of transplanted tumor in nude mice bodies.     

发酵木糖高产乙醇树干毕赤酵母菌株的Co60诱变选育

【目的】选育能够利用木糖高产乙醇的酵母菌株。【方法】采用Co60诱变树干毕赤酵母(Pichia stipitis),筛选乙醇产量高的突变菌株,并对原始菌株、突变菌株的生长发酵特性和两个菌株对高浓度木糖、乙醇的耐受性进行比较。【结果】在YPX培养基上筛选获得1株能够高效发酵木糖的突变菌株1K-9。该菌株在50mL 15%FM发酵84h,发酵液乙醇含量最高达(51.034±0.112)g/L,比原始菌株提高10.05%;在500mL 15%FM发酵96h,乙醇含量最高达(51.390±0.119)g/L;在500mL 20%FM发酵156h,乙醇含量最高达(52.496±0.513)g/L。菌株1K-9在HSM培养基或含4%~5%乙醇的YPX培养基中生长良好,在含6%~7%乙醇的YPX培养基中生长缓慢。【结论】Co60诱变对于树干毕赤酵母(Pichia stipitis)菌株是有效的,能选育出木糖高产乙醇酵母菌株1K-9。     

Assaying poly(ADP-ribose) polymerase activity in plants by polarographic method

A new method has been developed to assay poly(ADP-ribose) polymerase (PARP) activity in plant tissues through determining the content of nicotinamide (NIC) produced by enzymatic reaction by linear sweeping polarographic method. The detection limit of NIC was 0.03μmol/L, the calibration graph was linear up to 5 Mmol/L ( r = 0.999). The recoveries were approximately in the range of 92% to 98% and the relative standard deviations were less than 6.6% . Moreover, NAD+ and other interference existing in the mixture after enzymatic reaction had been removed by simple pretreatment, thus PARP assays were not interfered. A rapid, simple, sensitive and reliable nonisotopic method is reported to assay PARP activity in plant tissues . The results show that the KmNAD+ value of PARP in maize ( Zea mays L.) seedlings is 59 and the optimum pH for PARP activity is 8.5. Moreover, physiological conditions affect PARP activity in plant tissues, which has not been reported previously. When tobacco ( Nico-tiana tobacum) suspension cells were stressed by NaCI at low concentrations (100, 200 mmol/ L), the PARP activity increased significantly; when the cells were stressed at high concentrations (400, 1 000 mmol/L), it decreased to or even below the control level. PARP activity in etiolated maize seedlings was higher than that in light-grown seedlings.     

吸入白细胞介素-5对支气管哮喘患者外周血嗜酸性粒细胞数及其活化状态的影响

随机选择８例哮喘患者雾化吸入人重组ＩＬ－５,分别吸入前,吸入后２ｈ,２４ｈ和４８ｈ进行外周血有核细胞计烽和分类,以放射免疫法测定血清中嗜酸性阳离子蛋白（ＥＣＰ）及总ＩｇＥ水平,结果,吸入ＩＬ－５后嗜酸性粒细胞（ＥＯＳ）占细胞总数的百分比,ＥＯＳ绝对细胞数以及ＥＣＰ水平均随时间而明显升高,至２４ｈ达最高值,４８ｈ后仍维持在较高水平,ＩＬ－５在整个实验过程中对血清总ＩｇＥ水平无明显影响,表明,吸入ＩＬ     

Molecular source of biomarkers by genetic engineering techniques

The mutant lacking ORF469 fragment inSynechocystis sp. PCC 6803 (cyanobacterium) was created by means of DNA recombination. In its genome,ORF ₄₆₉, the key DNA fragment controlling the light-independent pathway of chlorophyll biosynthesis was deleted and replaced by erythromycin resistance cassette. The operation resulted in the fact that the content of chlorophyll in mutant cells was fully controlled by illumination and two kinds of cells were harvested, one is high chlorophyll with concentration of 9.427 μg· mg⁻¹ and the other is low chlorophyll with concentration of 0.695 μg · mg¹. They were subjected to thermal simulation respectively at 300°C for 100 h. The alkanes biomarkers from pyrolysates were analyzed by GC-MS and main difference between high and low chlorophyll cells was found at their contents of isoprenoid hydrocarbons. Pr/nC₁₇ and Ph/nC₁₈ from pyrolysate of low chlorophyll cells were 0.192 and 0.216 respectively, which were about 1/3 and 1/7 of that from high chlorophyll cells. The results provide direct evidence that isoprenoid hydrocarbons such as phytane(Ph) and pristane (Pr) could be derived from chlorophyll. The lipids in algal cells would be the most important contributors to hydrocarbon production in their thermal degradation. The results also indicated that the combination of molecular biology and organic geochemistry would provide a new path to investigate the molecular sources of biomarkers.     

An acetylcholinesterase inhibitor, 3-benzidino-5-methyl-6-phenylpyridazine, blocking outward potassium currents in acutely isolated rat hippocampal pyramidal neurons

3-benzidino-5-methyl-6-phenylpyridazine (BMP) inhibited electric eel acetylcholinesterase (AChE), with IC50 being 0.58 μmol·L-1. As an AChE inhibitor, the effects of BMP on delayed rectifier potassium current (IK(DR)) and transient outward potassium current (IK(A)) in acutely isolated rat hippocampal pyramidal neurons were studied using the whole cell patch-clamp technique. BMP (0.1―50 μmol·L-1) inhibited IK(DR) and IK(A) in a concentration-dependent and voltage-independent manner. The IC50 value for the bl...