十二烷基硫酸钠与十二烷基磺酸钠

十二皖基硫酸钠与十二垸基磺酸钠的混淆及误用具育一定的普遍性。两虽均属于阴离子表面活性剂但结构及理化性质均育所差别,因此在实验中予以一定的关注是必要的。     

Non-Immunological Precipitation of Serum by Sodium Dodecyl Sulfate in Agar Diffusion

Marmoset serum or serum of other species of animal may react with sodium dodecyl sulfate and forms nonspecific precipitin lines in agar diffusion. The protein detergent complexes are not readily dialyzable. Therefore precipitin lines derived from studies that use sodium dodecyl sulfate-treated antigens in agar diffusion must be interpreted with caution.     

Stopped-Flow Circular Dichroism Study on Conformational Change of Alpha-Chymotrypsin by Sodium Dodecyl Sulfate

Protein synthesis in dispersed cells from fetal liver was studied by fluorography of SDS-polyacrylamide gel electrophoresis of a [³⁵S]methionine labeled cell lysate. Synthesis of several proteins with molecular weights ranging from 45,000 to 220,000 was observed during erythropoiesis in fetal liver. Some of these proteins were demonstrated to be erythrocyte membrane proteins because they were immunoprecipitated with antiserum against rat red blood cells and the immunoprecipitation was competitive with non-radioactive proteins solubilized from erythrocyte ghosts. The same antiserum caused agglutination of dispersed cells from fetal liver. This supported the possibility that these proteins are translocated onto plasma membranes of the dispersed cells.     

Curing Action of Sodium Dodecyl Sulfate on a Proteus mirabilis R+ Strain

Growth of Proteus mirabilis harboring R100-1 (fi(+)drd str(r)cml(r)tet(r)sul(r)) factors in Penassay broth containing sodium dodecyl sulfate (SDS) leads to the loss of all or part of the genetic elements in high frequencies. In media containing SDS at concentrations as low as 0.03%, both lysis of R(+) cells and elimination of the R factors occur at high frequencies. Appearance of drug-susceptible cells in R(+) cultures occurs during the exponential phase of growth; however, the frequencies of susceptible cells increase substantially after the culture reaches the stationary phase. Reconstruction experiments, coupled with other observations, suggest that the major factor in altering the frequency of drug-susceptible variants is the greater resistance of the variants to the lytic action of SDS. This resistance correlates in most cases with the loss of the transfer functions in the resistance transfer factor.     

Enhancement by Sodium Dodecyl Sulfate of Pigment Formation in Serratia marcescens O8

Three methods were used to determine the enhancement by sodium dodecyl sulfate (SDS) of prodigiosin formation in Serratia marcescens O8. The results of the agar disk diffusion method indicated that pigment formation was dependent upon the concentration of SDS. Diameters of the pigment zones were proportional to the logarithm of SDS concentrations of 300 to 1,500 μg/ml. When bacteria were grown in broth containing SDS from 0 to 800 μg/ml and the pigment extracts were analyzed spectrophotometrically, a similar enhancement of pigment formation was observed. Finally, these results were confirmed by high-performance liquid chromatographic analysis of the extracts. Prodigiosin appeared to be the sole component with increased synthesis. The possible mechanism of the SDS enhancement effect could be explained by an increase in negative binding sites by the association of SDS with a cell envelope component(s). These binding sites may be required for prodigiosin synthesis.     

十二烷基硫酸钠对斑马鱼抗氧化能力的影响

以斑马鱼Brachyclanio rerio为实验对象,用不同浓度(0.5、3.0、18.0mg/L)的阴离子表面活性剂十二烷基硫酸钠(SDS)进行3、14、28、42、63d的暴露实验,通过测定肌肉组织中的总抗氧化能力(TAC)、超氧化物歧化酶(SOD)活性及丙二醛(MDA)含量三项指标研究SDS对斑马鱼抗氧化能力的影响。结果表明:0.5mg/L和3.0mg/L实验组SOD活性受到显著抑制(P<0.05),TAC水平和MDA含量与对照组无显著差异;18.0mg/L实验组在TAC水平和SOD活性上均表现为显著降低(P<0.05或P<0.01),MDA含量较对照和低剂量组亦有较大幅度增加,显示该组受试个体的抗氧化能力受到了显著抑制。研究结果对评价水环境中SDS毒性生物效应具有参考意义。     

The Dissociation of Wax Bean Hemagglutinin by Polyacrylamide Gel Electrophoresis in Sodium Dodecyl Sulfate

(+)-Biotin was synthesized from D-glucosamine in a sequence of 13 reactions.     

Specific Staining of Sialic Acid Components on Sodium Dodecyl Sulfate Polyacrylamide Gel

Specific staining of sialic acid components after sodium dodecyl sulfate polyacrylamide gel electrophoresis can be carried out as follows: 1) extract glycoprotein of erythrocyte membranes or serum by the phenol-saline method, 2) electrophorese the extract on 5% polyacrylamide gel containing 0.1% sodium dodecyl sulfate at constant current, 3) treat the gel with chilled 0.04 M HIO₄ for 45 minutes, 4) replace the periodic acid solution with one containing resorcinol 0.6 g, cone. HCl 50 ml, 0.1 M CuSO₄ 0.5 ml and H₂O 50 ml, 5) warm the container in boiling water until blue violet sialic acid bands become clear, 6) replace the staining solution with a mixture of equal parts water and concentrated HCl and observe at once.     

海藻酸钠与十二烷基聚氧乙烯醚硫酸钠复配体系泡沫及流变性能的研究

采用罗氏泡沫仪和流变仪对海藻酸钠(NaAlg)/十二烷基聚氧乙烯醚硫酸钠(AES)复配体系的起泡稳泡性能及流变行为进行研究,以探索NaAlg对AES起泡稳定性的影响及作用机理。泡沫性能试验显示,NaAlg的加入,提高了AES溶液的起泡能力及泡沫稳定性,溶液的pH值由7.0降到5.0,混合体系的起泡稳泡性明显增加。流变性研究展示,随着NaAlg浓度的增加,溶液的粘度呈增大的趋势,溶液总体呈现牛顿流体性质,当NaAlg浓度大于0.5%时,低剪切速率区,溶液仍呈现牛顿流体性质,而在高剪切速率区,有剪切变稀的现象出现。总体来看,各试液的G’相似文献   

Homogeneity of Envelope Proteins of Escherichia coli Separated by Gel Electrophoresis in Sodium Dodecyl Sulfate

Some envelope proteins of Escherichia coli show variable behavior in acrylamide gel electrophoresis in 1% sodium dodecyl sulfate, depending upon the conditions of the solubilization. When solubilized in 1% sodium dodecyl sulfate at 70 C for 20 min, three distinct peaks (peaks 4, 6, and 7) are seen at molecular weights of 57,800, 44,300, and 38,400, respectively. However, when the envelope fractions are solubilized in 1% sodium dodecyl sulfate at 100 C for 5 min, or when they are treated with N, N-dimethylformamide at acidic pH before solubilization by our method, only a single peak at 48,000 molecular weight is observed in the molecular weight range mentioned above. That is, peaks 4 and 7 disappear and a new peak appears at the position overlapping with peak 6. Proteins isolated from peaks 4 and 7 show the similar molecular weight shifts to the new peak by the treatment at 100 C. No other peaks show any change by the heat treatment. The increase at the new peak is completely accounted for by the decrease at peaks 4 and 7, indicating that the new peak is composed of proteins from peaks 4, 6, and 7. However, it is concluded that these three peaks consist of distinctly different proteins for the following reasons: (i) they have different amino acid compositions, (ii) they show different solubilities in the nonionic detergent, Nonidet P-40, and as shown previously, (iii) peak 6 (protein Y) is related to deoxyribonucleic acid synthesis, and (iv) proteins in peaks 4, 6, and 7 have different resistance to proteolytic enzymes. Although the reasons for the anomalous molecular weight shifts of these peaks are not well understood at present, it is important to solubilize the E. coli envelope proteins by the standard method in order to investigate their properties and functions of the envelope proteins.     

An Analysis of the Interaction of Sodium Dodecyl Sulfate with Lysozyme

The interaction of SDS with lysozyme was analyzed with enzyme activity and with NMR, fluorescence, and UV difference spectroscopies using various alkyl sulfates and variously modified lysozymes. SDS formed a stable complex with lysozyme without causing a gross conformational change in the enzyme molecule. Some SDS molecules bound to the active site cleft of lysozyme and therefore strongly inhibited the activity of lysozyme. Hydrophobic regions and positive charges for protein side, and a hydrophobic tail (possibly more than 8 carbons in alkyl chain) and a negative charge for detergent side were required for the formation of the complex.     

十二烷基磺酸钠纳米胶团-细胞色素c自组装高效纳米结构过氧化物酶

用阴离子表面活性剂十二烷基磺酸钠与细胞色素c自组装的方法构建了一种纳米超分子结构,观察到其具有显著的过氧化物酶活性,且在pH为10.5时达到最高。这种纳米结构过氧化物酶的催化效率为0.0219μmol/L.s。电化学方法测得其电子传递速率常数ks为0.586 s-1。这种以自组装方法构建的超分子结构不仅具有较高活性,可在天然过氧化物酶自杀性失活底物浓度较高时运用,且可固定化于电极上,实现与电极间的直接电子传递。     

Effects of Treatment with Sodium Dodecyl Sulfate on the Ultrastructure of Escherichia coli

An electron microscopy study has been made of the effects of dissolution of the plasma membrane of Escherichia coli with sodium dodecyl sulfate (SDS) on the organization of the nucleoplasm and the cytoplasm. The alterations observed in time course experiments were related to absorbance changes and to release of macromolecules from the cells. As the cells became plasmolyzed, under the conditions used, the first visible effect of SDS was a collapse of the plasmolysis spaces. This was accompanied by a displacement of the nuclear material which then appeared in broad contact with the redeployed plasma membrane. This initial displacement of nuclear material to the cell border may indicate an association between the nucleoplasm and the plasma membrane. Upon further dissolution of the plasma membrane, the nuclear material receded from the cell margin and contracted into an axial filament. Meanwhile, the cytoplasm dissociated into an amorphous, Pronase-sensitive component and an electron-opaque, granular one sensitive to ribonuclease. The latter represented one continuous area of ribosomal structures surrounding the nucleoplasm, an organization which did not occur when the cells were inhibited with rifamycin before SDS treatment. During prolonged SDS interaction, approximately 65% of the cellular protein, 25% of the ribonucleic acid and 40% of the deoxyribonucleic acid were released from the cells concomitant with the disappearance of the amorphous cytoplasmic part, expansion of the ribosomal aggregate, and rearrangement of the nuclear material at the cell periphery. The observations support the contention that all ribosomal structures bear a direct relationship with the nucleoplasm.     

Sodium Dodecyl Sulfate Hypersensitivity of clpP and clpB Mutants of Escherichia coli

We studied the hypersensitivity of clpP and clpB mutants of Escherichia coli to sodium dodecyl sulfate (SDS). Both wild-type E. coli MC4100 and lon mutants grew in the presence of 10% SDS, whereas isogenic clpP and clpB single mutants could not grow above 0.5% SDS and clpA and clpX single mutants could not grow above 5.0% SDS. For wild-type E. coli, cellular ClpP levels as determined by Western immunoblot analysis increased ca. sixfold as the levels of added SDS increased from 0 to 2%. Capsular colanic acid, measured as uronic acid, increased ca. sixfold as the levels of added SDS increased from 2 to 10%. Based on these findings, 3 of the 19 previously identified SDS shock proteins (M. Adamowicz, P. M. Kelley, and K. W. Nickerson, J. Bacteriol. 173:229-233, 1991) are tentatively identified as ClpP, ClpX, and ClpB.     

Comparison of In Vitro and Cell-Mediated Alteration of a Human Rhinovirus and Its Inhibition by Sodium Dodecyl Sulfate

After human rhinovirus type 2 (HRV-2) attaches to HeLa cells, two types of subviral particles are formed which closely resemble particles produced in vitro by acid or heat. One type of particle contains RNA whereas the second sediments as an empty capsid and is RNA-deficient. Sodium dodecyl sulfate (SDS) at 10(-4) M inhibits the cell-mediated formation of these particles from HRV-2 virions and the ability of HRV-2 to form plaques, but it does not inhibit the formation of plaques by human rhinovirus 14 (HRV-14). SDS also stabilizes HRV-2 against inactivation by acid or heat to a much greater extent than it does HRV-14. In a similar manner, SDS protects against the acid inactivation of the subpopulation of HRV-2 natural top component particles which attach to virus-specific cellular receptors. This suggests that the loss of native properties of natural top component particles and of virion are related processes. The basis for this alteration and also its role in infection are discussed.     

Heat-labile Enzymes in a Psychrophilic Bacterium

The oxidative and fermentative activities of a psychrophilic bacterium (strain 82), whose maximal growth temperature is 35 C, were completely destroyed by exposure of the cells to 46 C for about 1 hr, whereas those of mesophilic Escherichia coli were unaffected. Similar results were obtained with cell-free extracts. In attempts to determine some of the specific enzymes inactivated in strain 82 by exposure to 46 C, it was found that reduced nicotinamide adenine dinucleotide oxidase was completely inactivated at 46 C in 2 hr. Also, cytochrome c reductase was completely destroyed at 46 C in 1 hr and was 70% destroyed at 40 C in 2 hr. The heat lability of the latter may determine the maximal growth temperature of the organism. In addition, the results indicated that the enzymes of strain 82 involved in the clastic split of pyruvate to formate and acetate are inactivated by exposure to 46 C and that the lactic and glycerol dehydrogenases are more heat-labile than those in E. coli. Succinic, nicotinamide adenine dinucleotide phosphate-alcohol, and glucose-6-phosphate dehydrogenases, however, in both strain 82 and E. coli, were essentially unaffected by exposure to 46 C for 2 hr.     

Limited Hydrolysis of Ricin D with Trypsin in the Presence of Sodium Dodecyl Sulfate

An α-amylase which produces both maltotetraose and maltopentaose from starch as the main products was found in the culture filtrate of a strain of Bacillus circulans which was newly isolated from soil. The enzyme was purified to be almost homogeneous on disc electrophoresis in polyacrylamide gel by means of ammonium sulfate fractionation, DEAE-Sepharose column chromatography and Sephadex G-200 gel filtration.

The optimum pH and temperature of the enzyme were around pH 7.0 and around 50°C, respectively. Metal ions such as Hg²⁺, Cu²⁺, Ni²⁺, Zn²⁺, Fe²⁺ and Co²⁺ strongly inhibited the enzyme activity. The molecular weight was about 45,000. The yields of maltotetraose and maltopentaose from potato starch were 30 ~ 40% and 20 ~ 30%, respectively.     

Dissociation into Subunits of a 7S Protein in Soybean Globulins with Urea and Sodium Dodecyl Sulfate

A 7S protein isolated from soybean globulins was dissociated into a similar slow-sedimenting material (subunit) by the treatment of urea and sodium dodecyl sulfate (SDS).

Sedimentation coefficients of the subunits obtained by treating with 8 m urea and 0.25% SDS were 1.35 S and 2.00 S, and molecular weights were 22,500 and 34,000, respectively. These subunits by the both treatments were apparently different in conformation from the results of optical rotatory dispersion, i.e., urea treatment caused the almost complete unfolding of the subunit structure. On the contrary, SDS treatment contributed new partial formation of a α-helical conformation for the subunits.

These dissociations were extremely disturbed by the presence of sodium chloride.     

Effect of Sodium Dodecyl Sulfate on D-Glucose-isomerizing Enzyme from Bacillus coagulans,Strain HN-68

Crystalline D-glucose-isomerizing enzyme from Bacillus coagulans, strain NH–68 has been shown to consist of subunits by the method of electrophoresis on sodium dodecyl sulfate (SDS) polyacrylamide gels.

The dissociation behavior of the enzyme has been characterized. The enzyme dissociates into inactive subunits by the preincubation with 0.05% SDS in the presence of 5 × 10^?3M MnCl₂ or CoCl₂, but not in the absence of these metal salts. In 8 м urea, however, the enzyme does not dissociate into subunits and the activity is completely recovered by dilution of the urea. Metal salts, such as MnCl₂ and CoCl₂, also do not affect activity in the presence of urea.