十二烷基硫酸钠对多重耐药大肠埃希菌Ⅰ类整合子作用的初步探讨

目的探讨十二烷基硫酸钠(SDS)对多重耐药大肠埃希菌(E.coli)Ⅰ类整合子的作用。方法采用纸片扩散法(K-B法)测定71株大肠埃希菌对3类4种常用抗菌药物的药敏情况,聚合酶链反应(PCR)检测Ⅰ类整合子3个不同部位的基因。对经SDS处理的Ⅰ类整合子阳性多重耐药大肠埃希菌的Ⅰ类整合子基因与最低抑菌浓度(MIC)值进行测定与比较。结果 71株大肠埃希菌的多重耐药率为32.39%(23株),Ⅰ类整合子的总检出率为88.73%,不同部位基因检出率分别为:整合酶基因74.65%、遗传标记基因78.87%、可变区基因21.13%。SDS处理前、后多重耐药大肠埃希菌中的Ⅰ类整合子基因阳性率差异有统计学意义(P<0.05);对庆大霉素、头孢噻肟的MIC值差异均有统计学意义(P<0.05)。结论 SDS对多重耐药大肠埃希菌的Ⅰ类整合子有一定的影响。

重组白介素2在十二烷基硫酸钠溶液中的复性

采用在十二烷基硫酸钠（ＳＤＳ）溶液中加入铜离子的方法，观察了反应温度、ＣｕＣｌ＿２及ＳＤＳ浓度等因素对主组白介素２（ｒＩＬ－２）复性的影响。确定了能够明显减少二聚体形成的复性条件，可使ｒＩＬ－２反应浓度提高到１ｍｇ／ｍｌ。结果表明，复性后形成的二聚体低于１％（ＳＤＳ－ｐＡＧＥ），ｒＩＬ－２的比活性可达到１０￣７ｕ／ｍｇ。

健康成人皮肤对十二烷基硫酸钠刺激反应的反射式共聚焦显微镜特征分析

目的 观察十二烷基硫酸钠（SLS）刺激后18 - 60岁健康人皮肤反射式共聚焦扫描显微镜（RCM）特征的差异，分析年龄和性别对皮肤反应的影响，同时初步探讨RCM在客观评价皮肤反应中的价值。方法 采用封闭式斑贴试验，分别将0.1%和0.5% SLS贴敷于120例健康受试者背部48 h，并于去除后不同时间点进行临床评估和RCM检测。结果 0.1%和0.5% SLS组皮肤刺激反应的RCM特征主要有角化不全、角质层结构不清、棘层海绵水肿、表皮炎症细胞浸润和真皮乳突毛细血管扩张等。去除0.1%和0.5%SLS 刺激后24 h，RCM特征发生率达到高峰，其中真皮毛细血管扩张的发生率分别高达66.7%和95.0%。0.5% SLS去除后24 h，男性海绵水肿的发生率为68.9%（42/61），显著低于女性［84.7%（50/59），χ^2 = 4.24，P 〈 0.05］； 0.1%SLS去除后24 h，18 - 40岁年龄组人群棘层海绵水肿的发生率为53.3%（32/60），显著高于41 - 60岁［35.0%（21/60），χ^2 = 4.09，P 〈 0.05］；其余RCM参数，在0.1%和0.5% SLS刺激去除后，不同性别或不同年龄组之间差异均无统计学意义（P 〉 0.05）。临床评估显示去除0.1%和0.5% SLS后24 h，男女皮肤刺激反应发生率差异均无统计学意义（均P 〉 0.05），18 - 40岁和41 - 60岁两个年龄组之间差异也无统计学意义（均P 〉 0.05）。Spearman相关性分析显示，临床评估结果与RCM特征之间具有良好的相关性，其中，去除0.1% SLS后24 h，海绵水肿和真皮毛细血管扩张与临床评估结果的相关系数均高达0.77（P 〈 0.001）。但去除SLS 0.5 h后，0.1%和0.5% SLS组表现出2项以上RCM特征的受试者比例分别为17.5%（21/120）和51.7%（62/120），比同一时刻临床评估的阳性率［2.5%（3/120）和12.5%（15/120）］更接近去除SLS 24 h后的临床评估结果34.2%（41/120）和85.0%（102/120）。结论 性别和年龄对0.1%和0.5% SLS诱导的皮肤刺激反应无明显影响；相对临床评估，RCM在刺激反应早期能更加客观准确地评估皮肤反应。

组织工程心脏瓣膜支架构建的研究

目的:构建脱细胞猪主动脉瓣膜支架,为体外构建组织工程心脏瓣膜提供适宜的支架材料。方法:新鲜猪主动脉瓣叶,采用“低渗液-0.5%SDS-核酸酶”处理,进行大体、光镜、电镜观察和DNA含量测定。结果:“低渗液-0.5%SDS-核酸酶”可以完全脱去瓣膜细胞,同时较好地保持了胶原纤维和弹力纤维的原有排列和形态。结论:本方法可以成功构建脱细胞猪主动脉瓣膜支架,可进一步用于体外构建组织工程心脏瓣膜的研究。

细菌蛋白质组双向电泳中“串联珠”现象初探

目的初步探讨细菌样品双向电泳中"串联珠"状蛋白点产生的原因。方法通过对比不同样品制备方法对双向电泳胶图的影响,分析"串联珠"状蛋白点出现的条件,并取"串联珠"状蛋白点进行胶内酶解及MALDI-TOF/TOF分析,寻找"串联珠"状蛋白点可能产生的原因。结果以含0.5%SDS的裂解液煮沸菌体的方法制备样品,就会产生"串联珠"状蛋白点。蛋白鉴定结果显示"串联珠"状蛋白点为同一蛋白,MALDI-TOF/TOF一级质谱峰没有出现明显的偏移峰。结论 "串联珠"产生的原因是由于SDS在加热条件下会对蛋白产生修饰或紧密结合作用,特别是相对分子质量较大的酸性蛋白。

小鼠和沙鼠泡球蚴抗原ELISA诊断人泡球蚴病比较研究

通过 ELISA 法,比较研究了小鼠和沙鼠泡球蚴抗原(MAH&GAH抗原)计52例泡球蚴(AH)患者、59例非 AH 病患者和57名建康人的诊断价值。结果表明,MAH&-GAH 抗原的阳性率各为98.1%和100.0%,经统计学处理,两种抗原之间无显著差异;假阳性率两者相同,均为2.58%。但是,GAH 抗原在0.70以上高消光值中占96.15%,非常显著地高于MAH 抗原者(51.92%);抗体滴度在1:1600以上时,GAH 抗原占69.23%,也非常地高于MAH 抗原(占30.11%),按几何均数计,GAH 抗原为 MAH 抗原的2.87倍,说明诊断 AH 病宜用 GAH 抗原。以 SDS-PAGE 分离的蛋白质带带数,GAH 者为36条,MAH 者仅15条。

顺磁共振和紫外光谱法研究SDS-PEO体系的相互作用

合成更疏水的自旋探针 4羰基 2， 2， 6， 6四甲基哌啶氮氧自由基 2， 4二硝基苯腙 .用顺磁共振（ ESR）和紫外光谱法研究了十二烷基硫酸钠（ SDS） 0.5％ (w，质量分数 )聚氧乙烯（ PEO）体系的分子间相互作用 . ESR结果表明 ,此水溶液体系的微极性随 SDS浓度增大而减小，并且 SDS与 PEO聚集体具有更加紧密的堆积结构使其结合处具有较大的微粘性， SDS与 PEO间的相互作用导致 PEO分子链伸展 . UV表明自旋探针分子可能靠近胶束的表面存在， 2， 4二硝基苯肼基团可能位于靠近 SDS的硫酸根基团，定向于 SDS胶束的表面，氮氧自由基基团短距离渗透到 SDS胶束的碳氢核 .

Surface plasmon resonance-induced visible-light photocatalytic performance of silver/silver molybdate composites

Novel silver/silver molybdate（Ag/Ag2MoO4） composites with surface plasmon resonance（SPR）-enhanced photocatalytic performance were successfully fabricated via a facile one-pot hydrothermal route with the presence of sodium dodecyl sulfate（SDS） in this study.The as prepared silver/silver molybdate（Ag/Ag2MoO4） composites were systematically characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM） and ultraviolet-visible diffuse reflectance absorption spectroscopy（DRS） in order to investigate their crystal structure,morphology and optical property as well.The photocatalytic activities of the composites were subsequently evaluated by their ability to degrade rhodamine B（RhB） under visible-light irradiation.Varies of controlled experiments were then carefully operated to gain a deep insight into the assembling of Ag/Ag2MoO4composites.It was found that preparation conditions such as pH,reaction time,and the amount of surfactant played important roles in the formation of composites with octahedral microstructures.And the composite obtained at 160 ℃ using 0.5 g of sodium dodecyl sulfate exhibited the highest photocatalytic performance under visible-light irradiation.Capture experiments were also conducted to clarify the function of different active species generated on the surface of Ag/Ag2MoO4during the photocatalytic process,in which both holes and ·OH radicals were found to play crucial role in photocatalytic removal of RhB under visible light irradiation.A possible photocatalytic mechanism of Ag/Ag2MoO4 was finally proposed on the basis of all the results to explain the higher photocatalytic activity of the octahedral Ag/Ag2MoO4 composites.It was inferred that the photoinduced ＂hot＂ electrons can quickly transfer from the Ag NPs to the conduction band of Ag2MoO4 and react with oxygen and H2O to generate a large quality of active radicals such as ·OH and ·O2^- because of the SPR effects.Besides,this SPR effects of Ag nanoparticles deposited on the surface of Ag2MoO4 can not only dramatically amplify its light absorption,especially in the visible region,but also promote the separation of photoexcited electron-hole pairs and effectively decrease electron-hole recombination.

Curing of the Bacillus subtilis Plasmid Using Sodium Dodecyl Sulfate

Curing of Bacillus subtilis plasmid using sodium dodecyl sulfate (SDS)was studied in order to obtain a host strain. An overnight culture of Bacillus subtilis 24/pMX45 was used to inoculate fresh LB containing SDS (0-0.008%). No growth of 24/pMX45 was observed when LB contained an SDS concentration of 0.006% or greater, and the sublethal concentration (w/v) of SDS was 0.005% with a killing rate of 99%. Samples were diluted and plated on LB agar, individual colonies were randomly picked to a selective agar medium by tooth to screen for loss of plasmid-encoded erythomycin resistance. CsCl-EtBr gradient centrifugation and plasmid DNA profile demonstrated that plasmid-cured derivative A7 has completely lost its plasmid. A7 had a shorter lag, and its cell concentration was consistently higher than that of the 24/pMX45. Elimination of the plasmid was first observed after 24/pMX45 had been treated with SDS for 8 h. The percent elimination then continued to increase until about 22 h, after which the fraction of cured cell in the population remained constant. Plasmid cured cell numbers were measured in a separate control culture of 24/pMX45 untreated by SDS. No spontaneous loss of pMX45 was observed after 24/pMX45 were incubated for 24 h and 48 h with shaking at 37 ℃.These results suggested that SDS can be used as curing agent to eliminate the plasmid of Bacillus subtilis.

Rheological Behavior of Aqueous Solutions of Cationic Guar in Presence of Oppositely Charged Surfactant

The cationic guar （CG） is synthesized and the rheological behavior of aqueous solutions of CG in the presence of sodium dodecyl sulfate （SDS） is studied in detail. The steady viscosity measurements show that the zero shear viscosity enhancement can be almost 3 orders of magnitude as the concentration of SDS increases from 0 to 0.043%. The gel-like formation is observed as the concentration of SDS is greater than 0.016%. The oscillatory rheological measurements of CG solutions in the presence of SDS show that the crossover modulus is almost independent of the concentration of SDS whereas the apparent relaxation time increases swiftly upon increasing the concentration of SDS. The experimental results indicate that the strength rather than the number of the cross-links is greatly affected by SDS molecules. The mechanism concerning the effect of SDS upon the rheology of CG solutions can be coined by the two-stage model. Before the formation of cross-links at the critical concentration, the electrostatic interaction between SDS and cationic site of CG chains plays a key role and the SDS molecules bind to CG chains through the electrostatic interaction. After the formation of cross-links at the concentration greater than the critical concentration, the cooperative hydrophobic interaction become dominant and SDS molecules bind to the cross-links through the hydrophobic interaction. The theological behavior of aqueous solutions of CG in the presence of SDS is chiefly determined by the micelle-like cross-links between CG chains. In fact, the flow activation energy of CG solution, obtained from the temperature dependence of the apparent relaxation time, falls in the range of transferring a hydrophobic tail of SDS from the micelle to an aqueous environment.

录像记录斑贴试验

An unequivocal distinction between allergic and irritant patch test reactions is often difficult with patch tests. This study was designed to evaluate the worth of video- macro camera documentation for differentiation between allergic and irritant test reactions and to investigate whether there are characteristic clinical differences in patch test responses between metal salts and fragrances. Patch testing was performed with nickel sulfate, fragrance mix and an irritant, sodium lauryl sulfate 1% aq., on the upper back of 82 patients, with evaluation and computer- aided video documentation after 48 and 72 hr. No reliable clinicomorphological criterion was found for assessing a weak patch test reaction as being definitely allergic. Even characteristic papules and vesicles were not regularly found in allergic reactions. However, unlike fragrance mix, patch test reactions to nickel sulfate were characteristic in that they showed a heterogeneous spread and an association with hair follicle openings, independent of reaction intensity. Evaluation based on additional computer- aided video- macro camera documentation did not add further advantage for the differentiation of allergic and irritant reactions. But well- defined clinicomorphological features and reaction patterns to single test substances or even whole substance categories could be helpful additional criteria for evaluating patch test responses in clinical practice.

Functional conservation of the meiotic genes SDS and RCK in male meiosis in the monocot rice

The Arabidopsis SDS （SOLO DANCERS） and RCK （ROCK-N-ROLLERS） genes are important for male meiosis, but it is still unknown whether they represent conserved functions in plants. We have performed phylogenetic analyses of SDS and RCK and their respective homologs, and identified their putative orthologs in poplar and rice. Quantitative real-time RT-PCR analysis indicated that rice SDS and RCK are expressed preferentially in young flowers, and transgenic RNAi rice lines with reduced expression of these genes exhibited normal vegetative development, but showed significantly reduced fertility with partially sterile flowers and defective pollens. SDS deficiency also caused a decrease in pollen amounts. Further cytological examination of male meiocytes revealed that the SDS deficiency led to defects in homolog interaction and bivalent formation in meiotic prophase I, and RCK deficiency resulted in defective meiotic crossover formation. These results indicate that rice SDS and RCK genes have similar functions to their Arabidopsis orthologs. Because rice and Arabidopsis, respectively, are members of monocots and eudicots, two largest groups of flowering plants, our results suggest that the functions of SDS and RCK are likely conserved in flowering plants.

Intermolecular Interactions in Self-Assembly Process of Sodium Dodecyl Sulfate by Vertically Polarized Raman Spectra

Molecular self-assembly is extremely important in many fields, but the characterization of their corresponding intermolecular interactions is still lacking. The C-H stretching Raman band can reflect the hydrophobic interactions during the self-assembly process of sodium dodecyl sulfate （SDS） in aqueous solutions. However, the Raman spectra in this region are seriously overlapped by the OH stretching band of water. In this work, vertically polarized Raman spectra were used to improve the detection sensitivity of spectra of C-H region for the first time. The spectral results showed that the first critical micelle concentration and the second critical micelle concentration of SDS in water were 8.5 and 69 mmol/L, respectively, which were consistent with the results given by surface tension measurements. Because of the high sensitivity of vertically polarized Raman spectra, the critical micelle concentration of SDS in a relatively high concentration of salt solution could be obtained in our experiment. The two critical concentrations of SDS in 100 mmol/L NaCl solution were recorded to be 1.8 and 16.5 mmol/L, respectively. Through comparing the spectra and surface tension of SDS in water and in NaCl solution, the self-assembly process in bulk phase and at interface were discussed. The interactions among salt ions, SDS and water molecules were also analyzed. These results demonstrated the vertically polarized Raman spectra could be employed to study the self-assembly process of SDS in water.

Isolation of Lysozyme from Chicken Egg White Using Polyacrylamide-based Cation-exchange Cryogel

An effective cation-exchange chromatographic method for lysozyme isolation from chicken egg white is presented, using supermacroporous cryogel grafted with sulfo functional groups. The chromatographic processes were carried out by one-step and sequential elution, respectively. Sodium phosphate buffer （pH 7.8） containing different concentrations of NaC1 is used as elution agent. The corresponding breakthrough characteristics and elution behaviors in the cryogel bed were investigated and analyzed. Purity of lysozyme in the elution effluent was assayed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis （SDS-PAGE）. The maximum purity of the obtained lysozyme was about 96%, and the cryogel is demonstrated as a potential separation medium for purification of high-purit lysozyme from chicken egg white.

Influence of A-type Zeolite on Methane Hydrate Formation

The porous medium has an important effect on hydrate formation.In this paper,the formation process and the gas storage capacity of the methane hydrate were investigated with A-type zeolite and Sodium Dodecyl Sulfate (SDS) existing in the system.The results show that A-type zeolite can influence methane hydrate formation.At the temperature of 273.5 K and pressure of 8.3 MPa,the distilled water with A-type zeolite can form methane hydrate with gaseous methane in 12 hours.The formation process of the system with A-type zeolite was quite steady and the amount of A-type zeolite can influence the gas storage capacity significantly.The adding of A-type zeolite with 0.067 g·(g water)-1 into 2×10-3 g·g-1 SDS-water solution can increase the gas storage capacity,and the maximum increase rate was 31%.Simultaneously the promotion effect on hydrate formation of 3A-type zeolite is much more obvious than that of 5A-type zeolite when the water adding amounts are 0.033 g·g-1 and 0.067 g·g-1 at the experimental conditions.

An experimental study on thermal characteristics of nanofluid with graphene and multi-wall carbon nanotubes

High-thermal conductivity enhancement of nanofluid is one of the promising topics of the nanoscience research field. This work reports the experimental study on the preparation of graphene(GN) and multi-walled carbon nanotubes(MWCNTs) based nanofluids with the assistance of sodium dodecyl benzene sulfonate(SDBS) and sodium dodecyl sulfate(SDS) surfactants, and their thermal behaviors. The present work suggests not a solution, but a solution approach and deduces a new conclusion by trying to resolve the agglomeration problem and improve the dispersibility of nanoparticles in the base fluid. The analysis results of FESEM, thermal conductivity, diffusivity, effusivity and heat transfer coefficient enhancement ratio of nanofluid with surfactants SDS and SDBS expose strong evidence of the dispersing effect of surfactant on the making of nanofluid.

Bio-solubilization of Chinese lignite I:extra-cellular protein analysis

A white rot fungus strain, Trichoderma sp.AH, was isolated from rotten wood in Fushun and used to study the mechanism of lignite bio-solubilization.The results showed that nitric acid pretreated Fushun lignite was solubilized by T.sp.AH and that extracellular proteins from T.sp.AH were correlated with the lignite bio-solubilization results.In the presence of Fushun lignite the extracellular protein concentration from T.sp.AH was 4.5 g/L while the concentration was 3 g/L in the absence of Fushun lignite.Sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE) of the extracellular proteins detected at least four new protein bands after the T.sp.AH had solubilized the lignite.Enzyme color reactions showed that extracellular proteins from T.sp.AH mainly consisted of phenol-oxidases, but that lignin decomposition enzymes such as laccase, peroxidase and manganese peroxidases were not present.

Effect of bath composition and pulse electrodeposition condition on characteristics and microhardness of cobalt coatings

Nanocrystalline cobalt coatings were produced from cobalt sulfate based electrolytes by using pulse current electrodeposition technique.The effects of bath composition and electrodeposition condition on current efficiency,morphology,structure and hardness of the coatings were investigated and the optimum deposition condition was determined.It was found that increment of cobalt sulfate concentration and sodium dodecyl sulfate(SDS)concentration in the bath had a negligible effect on microhardness of the coatings,while they were effective on electrodeposition current efficiency.Adding saccharin to electrodeposition bath decreased crystallite size of hexagonal close-packed(hcp)cobalt films and increased their microhardness without significant effect on current efficiency.Smoother and less defective coatings were also obtained from baths containing SDS and saccharin.The results revealed that both the current efficiency and microhardness were changed by variation of peak current density and duty cycle.Besides change of smooth morphology of the coatings to needle-shaped one,crystallite sizes and preferred orientation also varied with increasing the current density and duty cycle.

Expression of Kaposi's Sarcoma-associated Herpesvirus ORFK8.1 and Its Preliminary Diagnostic Application

The ORFK8.1 of Kaposi＇s sarcoma associated-herpesvirus （KSHV） was expressed in a prokaryotic expression system. The expression of recombinant E.coli containing pQE-80L-orf KS.1 was induced by isopropyl-b-D-thiogalactopyranoside （IPTG）. The fusion protein was purified by chromatyography. The expressed protein and its purified product were identified by sodium dodecyl sulfate-polyacrylamide gel eletrophoresis （SDS-PAGE）. SDS-PAGE showed that a protein of 26 kDa was visualized as expected. A western blot assay was established to analyze the immunogenicity of purified recombinant ORFKS. 1 protein. The optimal condition of the recombinant ORFKS. 1 ELISA assay was confirmed： the concentration of antigen was 5 μg/mL, the dilution of serum was 1：200. We used the ELISA method to investigate the recombinant ORF KS. 1 protein＇s specificity, the data showed that the specificity of ORF KS.1 to detect KSHV was 100%. At the same time, 560 sera samples from Hubei province were detected by using ORFKS. 1 ELISA to investigate KSHV seroprevalence in this region. The KSHV seroprevalence in Hubei province is shown to be 6.80%.

Purification,Characterization and in vitro Anthelmintic Activity of a Neutral Metalloprotease from Laccocephalum mylittae

A neutral metalloprotease was purified from the cultured mycelia of Laccocephalum mylittae,an effective medicinal fungus widely used in anthelmintic therapy.The protease was purified to homogeneity with 31.85-fold purification and a final yield of 21.76%.The subunit molecular weight of the protease is about 40000 estimated by sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE).The optimum reaction pH and temperature are 7.5 and 50oC,respectively.The protease activity is largely enhanced by Ca2 +,but highly inhibited by tetrasodium ethylenediaminetetraacetate(EDTA),a metal-chelator,suggesting that the enzyme is a metalloprotease.The Michaelis-Menten constan Km and Vmax value for casein substrate are 6.09 mg·ml -1and 21.32μg·min -1·ml -1, respectively.In vitro anthelmintic tests of the protease exhibit distinct lethal effects on the third stage larvae(L3)of Ascaris suum.Scanning electron microscopy and SDS-PAGE analysis indicates that the proteolysis of larvae proteins caused by this protease may relate to the anthelmintic activity of L.mylittae.