Bioactivity and constituents of several common seaweeds

Bioactivity and constituents of 8 common seaweeds from Dalian intertidal zone of northern Yellow Sea were investigated. In the anti-methicillin-resistant Staphylococcus aureus (MRSA) test, Symphyocladia latiuscula and Enteromorpha intestinalis showed obvious activities with MICs much lower than 1.0 mg·mL-1 . In the DNA damage repair test (DDRT), Chondrus ocellatu showed selective inhibitory activity against the DNA repair-defective E. coli strain vs. the wild-type E. coli strain; while Sym. latiuscula, Enteromorpha intestinalis and Sar. kjellmanianum showed significant anti-E. coli activity with MICs of 64-128 g·mL-1 . In the anti-Pyricularia oryzae test, Sym. latiuscula and Rh. confervoides strongly inhibited the germination of the spores of P. oryzae on agar plate. In the brine shrimp larvicidal test, Sym. latiuscula, Rh. confervoides and Sar. kjellmanianum exhibited potent toxicity against brine shrimp larvae, with LC50 much lower than 1 mg·mL-1 . The HPTLC analysis revealed their diversified secondary metabolites. The HPLC-DAD-MS analysis of the strongest species Sym. latiuscula and database searching showed that it can produce quite diversified metabolites, including halogenated ones, some of which may be new natural products. The results demonstrated the potentials of these seaweeds in the development of new antibiotics, antitumor drugs, agricultural fungicides and pesticides.     

Characteristics of Baicalin Synergy with Penicillin or Notopterygium Ethanol Extracts Against Staphylococcus aureus

Introduction Staphylococcus aureus (S. aureus) resistance to most once powerful β-lactame antibiotics is now a severe problem world wide, so agents are urgently needed to reduce or moderate resistance to existing antibiotics. Traditional medicinal herbs …     

Spatial variability of cyanobacterial community composition in Sanya Bay as determined by DGGE fingerprinting and multivariate analysis

The cyanobacterial communities in the surface and bottom waters of Sanya Bay were investigated on April 24 and 25,2010.Flow cytometry showed that the total cyanobacterial abundance in the surface and bottom layers ranged from 0.7×10 4 to 2.38×10 4 cells mL-1 and from 1×10 4 to 1.8×10 4 cells mL-1,respectively.Cyanobacterial diversity was analyzed using a molecular fingerprinting technique called denaturing gradient gel electrophoresis(DGGE),followed by DNA sequencing.The results were then interpreted through multivariate statistical analysis.Differences in the compositions of cyanobacterial communities were observed in the surface and bottom waters at the same station,with some bands obtained from both the surface and bottom layers,whereas some bands were present only in one layer.The predominant cyanobacterial species of the excised DGGE bands were related to Synechococcus or Synechococcus-like species(56.2%).Other phylogenetic groups identified included Chroococcidiopsis(6.3%),Cyanobium(6.3%) and some unclassified cyanobacteria(31.2%).A redundancy analysis(RDA) was conducted to reveal the relationships between the cyanobacterial community composition and environmental factors.Analysis results showed that the spatial variations in the cyanobacterial community composition in surface waters was significantly related to chlorophyll a(Chla),the biochemical oxygen demand(BOD),nitrate and phosphate(P<0.05).Meanwhile,the spatial variations in the bottom waters was significantly affected by nitrate,nitrite,and phosphate(P<0.05).Environmental parameters could explain 99.3% and 58.3% of the variations in the surface and bottom layers,respectively.     

基于反应体系的表面增强拉曼光谱快速检测乙基麦芽酚

以铁离子(Fe~(3+))为媒介,鞣酸还原氯金酸制备的金纳米粒子(Au NPs)作为表面增强拉曼散射(SERS)基底,实现比色-散射光谱双响应,快速鉴别食品中的乙基麦芽酚.其中比色法中,对乙基麦芽酚的检测限为0.50 mg·mL~(-1).SERS检测中,利用Fe~(3+)和乙基麦芽酚的络合作用,乙基麦芽酚的最低检测限降低到0.01 mg·mL~(-1),线性范围为0.05～1.00 mg·mL~(-1).该方法使用的仪器简单,操作方便,可对样品中的乙基麦芽酚进行现场直接测定.     

药物中半胱氨酸的流动注射荧光测定方法研究

 在近中性介质及聚乙烯醇(PVA)存在下,半胱氨酸能熄灭一个新的荧光试剂5-(4-氯苯基)-8-苯磺酰氨基喹啉(CPBSQ)与Cu(Ⅱ)络合体系的荧光的反应.基于此现象,本文建立了一个测定半胱氨酸的流动注射荧光熄灭方法.结果表明,在λ_ex/λ_em=327/368nm处测定,方法的进样频率为64h-1,检测范围为0.05～5.5μg·mL^-1,检出下限为0.01μg·mL^-1,对4.0μg·mL^-1半胱氨酸平行测定11次的相对标准偏差为1.52%.大量存在的常见金属离子、蛋白质及很多不带巯基的氨基酸不干扰测定.应用此方法测定了某些注射液针剂中半胱氨酸的含量,结果满意.     

Spectrofluorimetric determination of magnesium (II) with 7-(8-Hydroxy-3, 6-disulfonaphthylazo)-8-hydroxyquinoline-5-sulfonic acid

A new fluorescent reagent, 7-(8-hydroxy-3, 6-disulfonaphthylazo)-8-hydroxyquinoline-5-sulfonic acid (HDNHQ) for the determination of magnesium has been developed. It reacted with magnesium to form a 1∶1 fluorescent complex withλ _ex/λ _em immediately at room temperature in ammonia-ammonium chloride buffer (pH 10.7). A linear relationship was obtained in the magnesium concentration range of 0–160 ng·mL⁻¹ with the detection limit of 0.04 ng·mL⁻¹. The proposed method was simple, rapid and sensitive. It has been successfully applied to the determination of trace magnesium in blood serum with recoveries of 103.75% and 98.16%, respectively. Foundation item: Supported by the Zi-Qiang Foundation of Wuhan University Biography: Zhang Xian (1975-), female, Ph. D candidant, research direction: organic reagent synthesis and analysis.     

Flow-injection microcolumn on-line preconcentration for the determination of chromium (VI)

A rapid and sensitive on-line preconcentration method for spectrophotometric determination of chromium (VI) in nature water is described. Preconcentration and determination are based on (i) the quantitative and fast adsorption of chromium (VI) on the high surface area nanometer-size TiO₂ (anatase) powders, which prepared by a sol-gel method from hydrolysis of TiCl₄ and (ii) the quantitative and reproducible elution of Cr (VI) by 2.0 mol·L⁻¹ HCl. A mini-column system for preconcentration is developed, Cr(VI) on the mini-column is eluted and merged with a stream water and DPCB (1,5-diphenylcarbazide) as the chromogenic reagent. The proposed system permits throughputs of 6 sample h⁻¹ (0.001 μg·mL⁻¹ Cr(VI)) or 20 sample h⁻¹ (0.1 μg·mL⁻¹ Cr(VI)). The preconcentration factor is 55. The detection limit is 0.8 ng · mL⁻¹ Cr(VI). The reproducibility is satisfactory with a relative standard deviation of less than 3.35% (0.01 μg·mL⁻¹ Cr(VI),n=5). Supported by the National Natural Science Foundation of China Ma Wanhong: born in 1961, Ph. D. Graduate student, Associate professor     

Separation of four -lol drugs by HPLC with new bonded chiral stationary column

Separation of betaxolol, bevantolol, metoprolol, bisoprolol with new bonded chiral stationary (3,5-dimethylcabamate cellulose) Chiralpak IB column was investigated. The factors, such as mobile phase composition and the ratio, column temperature, flow rate and the proportion of chiral additives, were also investigated. The optimal mobile phase compositions of betaxolol, bevantolol, metoprolol, bisoprolol were n-hexane/ethanol (95/5, v/v; 0.2% DEA); n-hexane/ethanol (90/10, v/v; 0.1% DEA); hexane/ethanol (60/40, v/v; 0.1% DEA); n-hexane/ethanol (95/5, v/v; 0.2% DEA), respectively. The optimal temperature was 30℃ with a flow rate of 0.8 mL min-1 . The detection wavelength, by 1200VWD UV detector, of betaxolol, bevantolol, metoprolol, bisoprolol was 259, 274, 224 and 223 nm, respectively. Experimental results demonstrated that baseline separation (Rs>1.5) of the betaxolol, bevantolol, metoprolol, bisoprolol enantiomers were obtained with new bonded Chiralpak IB column. This method can be used for analysis and detection of these four drugs.     

Determination of both jasmonic acid and methyl jasmonate in plant samples by liquid chromatography tandem mass spectrometry

An efficient method for the simultaneous extraction and quantification of both jasmonic acid (JA) and methyl jasmonate (MeJA) from a single plant sample was developed. Plant tissues were firstly extracted by using 100% cold methanol, then the Sep-pak C₁₈ solid-phase extraction (SPE) cartridges were adopted for the purification of sample extract, and finally JA and MeJA were deter-mined by the liquid chromatography tandem mass spectrometry (LC-MS-MS) system. It was found that the accuracy was improved by using the extra standard for the estimation and correction of JA and MeJA losses in the extraction and purification process. The detection limits for JA and MeJA were 0.03 and 0.075 ng mL⁻¹, respectively, and the average recovery rate of JA and MeJA was 92.48% and 94.30%. The method was found to be reproducible and selective, yielding well isolated and easily detectable peaks for both JA and MeJA and simplifying the time-consuming extraction and purification. High-performance liquid chromatography (HPLC) system was employed as the control detection method for the LC-MS-MS system. The two systems were compared in their specificity and accuracy.     

Efficient transfer and expression of human clotting factor IX cDNA in neonatal hemophilia B mice mediated by VSV-G pseudotyped retrovirus

The feasibility of in vivo gene therapy for hemophilia B by VSV-G pseudotyped retroviral vector was introduced. The novel packaging cell line 293GPG was used to produce VSV-G/G1NaBAIX pseudotyped virus with the highest titers up to 8.5×10⁸ cfu·mL^-1. In contrast to the conventional retrovirus, VSV-G pseudotyped virus was more resistant to inactivation by serum complements (P＜0.001). Our results also demonstrated that VSV-G pseudotyped virus was more stable in neonatal mice serum than in adult mice serum (P＜0.01). After intraperitoneal injection of different doses of virus, hFIX antigen was detected and lasted for more than 120 d, the highest level reached (72.5±6.1) ng·mL^-1. Moreover, the functional activity was improved to some extent in all hFIX-treated mice, the most remarkable improvement was observed in the mice treated with higher dose of virus whose clotting activity increased to (3.4±1.5)% and APTT (activated partial thromboplastin time) reduced to (43.2±7.2) s. The anti-hFIX antibody was not detected by the method of Bethesda, no germ line transmission and any side effects associated with gene transfer were found. Our results indicated that neonatal gene therapy for hemophilia B mice by VSV-G pseudotyped retrovirus is promising.     

Preparation,characterization and antibacterial property of naringin loaded PLGA nanospheres

Naringin is a predominant flavanone in grapefruit and shows a variety of biological effects such as antioxidative, anticancer, anti-inflammatory and antibacterial activity. However, its application in pharmaceutical field is limited by low water solubility, poor bioavailability and instability. To overcome the problem, naringin has been encapsulated in poly(lactic-co-glycolic acid) (PLGA) polymer by emulsion-diffusion-evaporation method in this work. Moreover, naringin loaded PLGA nanospheres were characterized by scanning electron microscope (SEM), dynamic light scatter method (DLS), fourier transform infrared (FTIR) spectra, UV–vis spectra and fluorescence spectra of DNA-EB competition displacement. The mean diameter of PLGA nanospheres and NRG/PLGA nanospheres was 123 ?± ?25 ?nm and 137 ?± ?30 ?nm, respectively. The drug encapsulation efficiency was 86.4% while the drug loading rate was 22.3%. The fluorescence spectra of the competitive DNA-binding experiments revealed that the functional activity of naringin was retained after loaded in PLGA. It is revealed that the initial burst effect happened in the initial 24 ?h and followed by sustained release lasting for 10 days. Moreover, the nanospheres exhibited strong antibacterial activity, and 99.9% of E. coli and S. aureus were killed when treated with naringin loaded PLGA nanospheres at the concentration of 0.2 ?mg ?mL^?1 within 24 ?h. Furthermore, the viable cells remained only 48% when the concentration of NRG/PLGA nanospheres was 32 ?μg ?mL^?1 and NRG/PLGA nanospheres was important for inhibition of cancer cells. It is concluded that the stable naringin loaded PLGA nanospheres could have potential application in food industry and nanomedicine field.     

Determination of ciprofloxacin hydrochloride in pharmaceutical preparation and biological fluid by Rayleigh light scattering technique

A highly sensitive and simple Rayleigh light scattering (RLS) method for determination of ciprofloxacin hydrochloride has been developed. Ciprofloxacin hydrochloride (CPFH) reacted with tetraphenylboron sodium(TPB) to form an ion-association complex in pH 5.31 aqueous solution, which resulted in a significant enhancement of the RLS intensity, which was linear with the concentration of CPFH in the range of 12.7–419 ng·mL⁻¹. The limit of detection for CPFH was 6.99 ng·mL⁻¹. The method is simple, highly sensitive and selective within a wide linear range. Appliying this method to determination of ciprofloxacin hydrochloride in pharmaceutical preparations and biological fluids obtained satisfactory results. Foundation item: Supported by the National Natural Science Foundation of China(20675059) and Research Foundation of Leshan Teachers’ College, China (Z0625)     

Hot deformation characteristics of as-cast high-Cr ultra-super-critical rotor steel with columnar grains

Isothermal hot compression tests of as-cast high-Cr ultra-super-critical (USC) rotor steel with columnar grains perpendicular to the compression direction were carried out in the temperature range from 950 to 1250°C at strain rates ranging from 0.001 to 1 s-1. The softening mechanism was dynamic recovery (DRV) at 950°C and the strain rate of 1 s-1, whereas it was dynamic recrystallization (DRX) under the other conditions. A modified constitutive equation based on the Arrhenius model with strain compensation reasonably predicted the flow stress under various deformation conditions, and the activation energy was calculated to be 643.92 kJ·mol-1. The critical stresses of dynamic recrystallization under different conditions were determined from the work-hardening rate (θ)–flow stress (σ) and -?θ/?σ–σ curves. The optimum processing parameters via analysis of the processing map and the softening mechanism were determined to be a deformation temperature range from 1100 to 1200°C and a strain-rate range from 0.001 to 0.08 s-1, with a power dissipation efficiency η greater than 31%.     

A new estimate of global soil respiration from 1970 to 2008

Soil respiration(Rs)is one of the key processes that underline our understanding of carbon cycle in terrestrial ecosystems.Great uncertainty remains in the previous global Rs estimates with a difference of 70 Pg C a 1between the highest and lowest estimates.Thus,the present study aimed to estimate the global annual Rs and investigate the interannual and spatial variability in global annual Rs using a semi-mechanistic,empirically-based model which included climatic factors(temperature and precipitation)and topsoil(0–20 cm)organic carbon storage.About 657 published studies of annual Rs from 147 measurement sites were included in this meta-analysis.The global data sets from 1970 to 2008 on climate,surface air temperature,and soil properties were collected.The Monte Carlo method was used to propagate the simulation errors to global Rs.The results indicated that the mean annual global Rs was 94.4 Pg C a 1,increasing at roughly 0.04 Pg C a 1(~0.04%a 1)from 1970 to 2008.The Rs rate increased from colder,drier and less soil carbon-rich regions to warmer,moister and more carbon-rich regions.Highest Rs rates appeared in the tropical forest,while the lowest ones were in polar and desert regions.The annual Rs correlated directly with global temperature anomalies,suggesting that the interannual variability in temperature was responsible for the interannual variations in predicted global Rs.The global Rs increased from high-latitude zones to low-latitude zones.Further studies are recommended to explore the relationship between soil respiration and vegetation characters.     

ICP-MS分析复方甘草口服溶液中15种元素

建立电感耦合等离子体质谱(ICP-MS)法测定复方甘草口服溶液中15种元素(Cr、Mn、Co、Ni、Cu、Zn、As、Cd、Sn、Sb、Ba、Hg、Pb、Al、Fe)。样品经微波消解后,根据待测元素的质量数选择相应元素作为内标,采用碰撞模式(氦模式)进行测定。结果显示,15种元素线性关系良好,相关系数均大于0.999,各元素的检出限在0.08～38.00ng·mL~(-1),回收率在88.57%～107.10%(n=6)。该方法操作简便,分析速度快,灵敏度高,线性范围宽,可同时测定多种元素,适用于复方甘草口服溶液中元素的测定。     

乳酸菌计数结果的比较研究

通过流式细胞术(FCM),利用SYTO?24与PI双染色对发酵乳制品即发酵乳饮料和发酵乳中的乳酸菌进行快速检测,并将检测结果与用现行国标中推荐的平板计数法检测得到的结果相比较,两者对发酵乳饮料和发酵乳中乳酸菌的计数结果的相关性系数分别为:0. 9014;和0. 9653,都符合较好.而且FCM稳定性更好,活性细菌的变异率为3. 46%,非活性细菌的变异率为3. 56%;检测速度更快,单样品检测时间不超过10 min;灵敏度更高(10~3AFU·mL~(-1)) FCM在需要快速放行的液体产品检测领域中具有广阔的应用前景.     

Reductive immobilization of perrhenate in soil and groundwater using starch-stabilized ZVI nanoparticles

Perrhenate(ReO4-) was used as nonradioactive surrogate for the radionuclide pertechnetate(99TcO-4) to investigate the potential of using starch-stabilized zero valent iron(ZVI) nanoparticles for reductive immobilization of pertechnetate in soil and groundwater.Batch kinetic tests indicated that the starch-stabilized ZVI nanoparticles were able to reductively remove ～96% of perrhenate(10 mg/L) from water within 8 h.XRD analyses confirmed that ReO 2 was the reduction product.A pseudo-first-order kinetic model was able to interpret the kinetic data,which gave a pseudo first order rate constant(kobs) value of 0.43h-1 at pH 6.9 and room temperature(25℃).Increasing solution pH up to 8 progressively increased the reaction rate.However,highly alkaline pH(10) resulted in much inhibited reaction rate.Consequently,the optimal pH range was identified to be from 7 to 8.Increasing solution temperature from 15 to 45℃ increased k obs from 0.38 to 0.53 h-1.The classical Arrhenius equation was able to interpret the temperature effect,which gave a low activation energy value of 7.61 kJ/mol.When the ReO-4-loaded loess was treated with the stabilized nanoparticles suspension([Fe]=560 mg/L),the water leachable ReO-4 was reduced by 57% and nearly all eluted Re was in the form of ReO2.This finding indicates that starch-stabilized ZVI nanoparticles are promising for facilitating in situ immobilization of ReO-4 in soil and groundwater.     

Response of leaf dark respiration of winter wheat to changes in CO2 concentration and temperature

Accurate evaluation of dark respiration of plants is important for estimation of the plant carbon budget.The response of leaf dark respiration of winter wheat to changes in CO 2 concentration and temperature was studied,using an open top chamber during 2011-2012,to understand how leaf dark respiration of winter wheat will respond to climate change.The results indicated that leaf dark respiration decreased linearly with increased CO2 concentration.Dark respiration decreased by about 11% under 560 μmol mol-1 CO2 compared with that under 390 μmol mol-1 CO2.Leaf dark respiration showed an exponential relationship with temperature,and the temperature constant(Q10) was close to 2.Moreover,the responses of leaf dark respiration to CO concentration and temperature were independent.A leaf dark respiration model based on CO2 concentration and temperature responses was developed.This model provides a method for estimation of the leaf dark respiration rate of winter wheat under future climate change and guidance for establishment of crop carbon countermeasures.     

Organotin compounds in surface sediments from selected fishing ports along the Chinese coast

The concentrations and species of organotin compounds(OTCs) in 52 surface sediment samples from nine fishing ports along the Chinese coast were studied.Butyltins(BTs) and phenyltins(PhTs) were derivatized using sodium tetraethylborate(NaBEt 4) and determined by head-space solid-phase microextraction(HS-SPME) gas chromatography coupled with a flame photometric detector(GC-FPD).The concentrations of OTCs ranged from <3.6 to 194 ng(Sn) g-1 dry weight(dw) for monobutyltin(MBT),<2.3 to 41.5 ng(Sn) g-1 dw for dibutyltin(DBT),<0.7 to 86.0 ng(Sn) g-1 dw for tributyltin(TBT) and <5.1 to 66.1 ng(Sn) g-1 dw for monophenyltin(MPhT),respectively.The concentrations of diphenyltin(DPhT) and triphenyltin(TPhT) were below the limit of detection(LOD).BTs were the main species in the sediments except for the samples collected from Shazikou fishing port in Qingdao.The concentrations of MBT were higher than DBT and TBT.The concentrations of OTCs in the sediments varied widely among different sampling locations.The concentrations of BTs were much higher in the samples collected from fishing ports close to the South China Sea than those in coast of the East China Sea and the Yellow Sea.MPhT was prevalent in most sampling stations except for those in coast of the East China Sea.The environmental and ecotoxicological risks of TBT in most sediment samples were low.