Resonance light scattering technique for the determination of proteins with Congo red and Triton X-100.

Resonance light scattering (RLS) of Congo red (CR) was greatly enhanced by BSA (HSA) in the presence of Triton X-100 (TX-100). In sodium citrate-HCl buffer (pH 2.7-3.0), the enhanced intensity of resonance light scattering at 360 nm was in proportion to the concentration of proteins [corrected] The linear relationship was obtained between the resonance light scattering intensity and proteins in the range 5.0 x 10(-8)-8.0 x 10(-6) g/mL and 1.0 x 10(-9)-6.0 x 10(-6) g/mL for BSA and HSA, respectively. Their detection limits were 1.4 x 10(-8) g/mL and 2.8 x 10(-10) g/mL (S:N = 3), respectively. Synthetic and actual samples were analysed satisfactorily.     

Selective determination of cysteine by resonance light scattering technique based on self-assembly of gold nanoparticles

The interaction between cysteine and gold nanoparticles was studied. Through the covalent combination with the -SH group and the electrostatic binding with the -NH3+ group of cysteine, gold nanoparticles can self-assemble to form a network structure, which results in greatly enhanced resonance light scattering (RLS). The experimental results demonstrate that the RLS technique offers a sensitive tool for investigations of self-assembly of nanoparticles. On the other hand, the RLS method can be applied to selectively determine cysteine with high sensitivity and simple operation. The linear range of determination of cysteine is from 0.01 to 0.25 microg/mL with the detection limit of 2.0 ng/mL (16.5 nM, 3sigma). None of the amino acids found in proteins interferes with the determination.     

微生物降解多氯联苯的研究进展

多氯联苯是一种持续性有机污染物,在自然环境中很难降解。在目前研究的降解方法中,微生物降解最具潜力。本文对多氯联苯微生物降解的研究进展进行了综述,包括厌氧还原脱氯,好氧氧化以及生物表面活性剂的作用,介绍了几种降解方法耦合应用的现状和前景,指出了应用中存在的问题和今后的发展方向。     

零价金属降解多氯联苯(PCBs)

多氯联苯(polychlorinated biphenyls,简称PCBs)是一类对环境有不利影响的有毒有机物,它在环境中广泛而大量分布。许多科学家都在致力于有效处理PCBs污染介质(包括水、油、沉积物和土壤)的修复技术的研究。本文综述了国内外在零价金属还原脱氯降解PCBs领域的研究状况。在高温等特殊条件下或有钯、铂、镍和铜等催化剂存在的条件下,零价金属能有效促进PCBs还原脱氯。讨论了零价铁还原脱氯的3个可能的途径:金属直接反应,将零价铁表面的电子转移到有机氯化物使之脱氯;铁腐蚀的直接产物Fe2 具有还原能力,它可使得一部分氯代烃脱氯;铁反应产生的氢气可使有机氯化物还原。评述了零价金属还原脱氯PCBs具有有效、廉价和易得的特点。展望了零价金属还原脱氯降解PCBs研究领域的发展前景。     

Resonance light scattering determination of trace bisphenol A with signal amplification by aptamer–nanogold catalysis

HAuCl₄ was reduced by sodium citrate to prepare 10 nm gold nanoparticles (AuNPs) that were modified by the bisphenol A aptamer (Apt) to obtain an aptamer–nanogold probe (Apt‐AuNP) for bisphenol A (BPA). The probes were aggregated nonspecifically to form large clusters, which showed a strong resonance light scattering (RLS) peak at 520 nm, under preparation conditions (pH 7.6 Na₂HPO₄‐NaH₂PO₄ buffer and ultrasonication). Upon addition of BPA, the probe reacted specifically to form dispersed BPA‐Apt‐AuNP conjugates that exhibited strong catalysis of the two particle reactions of glucose‐Cu(II) and hydrazine hydrochloride‐Cu(II) with a strong RLS peak at 360 nm and 510 nm respectively. When the BPA concentration increased, the RLS intensity at 360 nm and 510 nm increased respectively. Accordingly, two new and highly‐sensitive RLS methods were established for the detection of BPA, using the Apt‐AuNP catalytic amplification. Copyright © 2013 John Wiley & Sons, Ltd.     

Protein analysis with tetra-substituted sulfonated cobalt phthalocyanine by the technique of Rayleigh light scattering

This is the first report of cobalt-tetrasulfonatophthalocyanine (CoTSPc) as a probe of Rayleigh light scattering (RLS) to determine proteins at nanogram levels. A highly sensitive method has been developed for the determination of proteins by the light scattering technique on a common spectrofluorimeter, based on the fact that the weak RLS of CoTSPc can be greatly enhanced in the presence of proteins. Under optimum conditions, the linear ranges of the calibration curves were 0.10-34.3 microg x mL(-1) for both human serum albumin and bovine serum albumin, with detection limits of 15.5 and 13.9 ng x mL(-1), respectively. Moreover, there is almost no interference of any amino acids and metal ions. The method has been applied to the direct determination of total proteins in human serum samples, and the results were satisfactory with clinical data provided.     

多氯联苯的生物修复

多氯联苯(Polychlorinated biphenyls,PCBs)是一种持久性有机污染物,对人类和自然环境具有很大的威胁,降解PCBs一直是研究的热点。在目前的研究方法中生物降解最具潜力,生物降解主要分为微生物降解、植物修复和微生物-植物共同修复3个方面。文章着重介绍了微生物降解PCBs菌株的分离,降解相关基因的克隆和改造;同时对植物修复,植物与微生物共同修复以及植物转基因修复进行了讨论。     

A label-free visual immunoassay on solid support with silver nanoparticles as plasmon resonance scattering indicator

By taking silver nanoparticles (Ag-NPs) as plasmon resonance scattering (PRS) indicator considering that Ag-NPs have strong plasmon resonance light scattering signals corresponding to their plasmon resonance absorption (PRA), we propose a label-free visual immunoassay on the solid support of glass slides. Our investigations showed that Ag-NPs could be adsorbed on the surface of glass slides where immunoreactions between a previously immobilized antigen and its antibody have occurred if the glass slides were immersed in an Ag-NP suspension whose pH value has been carefully adjusted. The optimal pH of the Ag-NP suspension depends on the nature of previously immobilized antigen and its antibody. It was found that the adsorption of negative-charged Ag-NPs on the surface of glass slides depends only on the content of antibody under optimal conditions. With a common spectrofluorometer to measure the PRS signals of the Ag-NPs adsorbed on the surface, we could detect antibody in the range of 10 to 160 ng ml⁻¹. If a white light-emitting diode (LED) torch is employed to illuminate the glass slides, we can make visual detection of the antibody by the naked eye.     

On the inhibition of microsomal drug metabolism by polychlorinated biphenyls (PCB) and related phenolic compounds.

The in vitro metabolism of p-nitroanisole, aminopyrine, and aniline by rat liver microsomal monoxygenases were studied in the presence of different polychlorinated biphenyl (PCB) mixtures and some related hydroxybiphenyls. The tested PCB mixtures contained preferably dichloro- (di-CB), tetrachloro- (tetra-CB), or hexachlorobiphenyls (hexa-CB). All PCB were competitive inhibitors of only aminopyrine demethylation by normal microsomes (Ki 22-39 micron). In microsomes of PCB-pretreated rats the aminopyrine demethylation was inhibited noncompetitively by di-CB and hexa-CB whereas tetra-CB remained a competitive inhibitor (Ki 12 micron). Moreover, after PCB pretreatment all PCB were competitive inhibitors of p-nitroanisole demethylation. 2-OH-biphenyl and 4-OH-biphenyl caused competitive inhibition of aminopyrine demethylation and aniline hydroxylation but failed to inhibit p-nitroanisole metabolism by normal microsomes. Chlorinated 4-hydroxybiphenyls inhibited competitively the metabolism of both type I and type II substrates. However, after PCB pretreatment all phenolic compounds caused uncompetitive inhibition of aniline hydroxylation.     

Eco-physiological responses of Polytrichum commune to soil contamination by polychlorinated biphenyls

 通过微体繁殖技术在多氯联苯(PCBs)污染土壤基质上进行大金发藓(Polytrichum commune)的室内培养, 研究了不同浓度(5、10和20 mg·kg^–1)低氯PCBs (Aroclor 1242)和高氯PCBs (Aroclor 1254)对大金发藓生理生态指标的影响。经6个月的培养, 大金发藓的密度和盖度分别达93%和50株·cm^–2以上, PCBs处理组与对照组相比无显著差异, 表明PCBs对大金发藓茎叶碎片再生成新植株体的能力没有产生不利影响。大金发藓鲜质量和株高随低氯PCBs (Aroclor 1242)浓度增加而增加、随高氯PCBs (Aroclor 1254)浓度增加而减小, 但均高于对照, 表明PCBs处理对大金发藓的生长具有一定的促进作用。PCBs处理组大金发藓叶绿素a、b以及叶绿素a + b含量较对照组有所增加, 叶绿素a/b值与对照组相比基本没有变化。PCBs处理组大金发藓膜脂过氧化产物丙二醛含量和超氧化物歧化酶活性与对照组相比无显著差异, 谷胱甘肽含量较对照组显著增加, 表明谷胱甘肽在大金发藓体内活性氧清除过程中起重要作用。总体来看, 大金发藓能在所设浓度的PCBs范围内正常生长, 对PCBs有较强的耐性。     

大金发藓对土壤多氯联苯污染的生理生态响应

通过微体繁殖技术在多氯联苯(PCBs)污染土壤基质上进行大金发藓(Polytrichum commune)的室内培养, 研究了不同浓度(5、10和20 mg·kg^-1)低氯PCBs (Aroclor 1242)和高氯PCBs Aroclor 1254)对大金发藓生理生态指标的影响。经6个月的培养, 大金发藓的密度和盖度分别达93%和50株·cm^-2以上, PCBs处理组与对照组相比无显著差异, 表明PCBs对大金发藓茎叶碎片再生成新植株体的能力没有产生不利影响。大金发藓鲜质量和株高随低氯PCBs (Aroclor 1242)浓度增加而增加、随高氯PCBs (Aroclor 1254)浓度增加而减小, 但均高于对照, 表明PCBs处理对大金发藓的生长具有一定的促进作用。PCBs处理组大金发藓叶绿素a、b以及叶绿素a + b含量较对照组有所增加, 叶绿素a/b值与对照组相比基本没有变化。PCBs处理组大金发藓膜脂过氧化产物丙二醛含量和超氧化物歧化酶活性与对照组相比无显著差异, 谷胱甘肽含量较对照组显著增加, 表明谷胱甘肽在大金发藓体内活性氧清除过程中起重要作用。总体来看, 大金发藓能在所设浓度的PCBs范围内正常生长, 对PCBs有较强的耐性。     

Activity of nitrifying populations in grassland soil polluted by polychlorinated biphenyls (PCBs)

The activity of nitrification was studied in the period of 1992 – 1994 in two grassland plots from the surroundings of a municipal waste incinerator. The soil parameters were fully comparable in both plots and the soils differed in the level of polychlorinated biphenyls (PCBs). The concentration of PCBs found in Klajdovka-control plot (KL): 4.4 ng g_{dry soil} ^–1 can be regarded as a background value, while the polluted plot, Bílá Hora (BH), contained increased amount of PCBs: 14.0 ng g_{dry soil} ^–1.The following parameters of nitrifying activity were determined: field concentrations of N_inorg species, mineralization potentials, nitrifying activity during long-term laboratory incubations, and the potential activity of both ammonium and nitrite oxidizers in short-term incubations in soil slurries. Simultaneous application of all these methods appeared to be very suitable for reliable assessment of nitrifying activity in the field.In the case of the polluted plot, the abnormal accumulation of nitrite was observed both in the field (e.g. in September 1992: BH-656.8 ng NO _inf2 ^– -N g_{dry soil} ^–1; KL-208.2 ng NO _inf2 ^– -N g_{dry soil} ^–1) and in the laboratory incubations. Furthermore, the capability of the polluted plot to nitrify higher amount of ammonium nitrogen appeared to be significantly reduced due to detrimental changes in the activity of nitrite-oxidizing community. In contrast to the nitrification, the mineralization potential did not differ between the plots throughout the sampling period.     

Resonance Rayleigh scattering method for the determination of chitosan with some anionic surfactants

In weak acidic buffer medium, chitosan binding with an anionic surfactant, such as sodium dodecyl benzene sulphonate (SDBS), sodium lauryl sulphate (SLS) or sodium dodecyl sulphonate (SDS), can result in a significant enhancement of resonance Rayleigh scattering (RRS) intensity. The results showed that under optimum conditions the enhanced RRS intensity is proportional to the concentration of chitosan in the range 0.10–20.0 µg/mL for SDBS, 0.27–15.0 µg/mL for SLS and 0.20–15.0 µg/mL for SDS. Among these, the sensitivity of SDBS is the highest and its detection limit for chitosan is 29 ng/mL, while those of SLS and SDS are 83 and 61 ng/mL, respectively. The method has good selectivity and was applied to the determination of trace amounts of chitosan in practical samples with satisfactory results. Therefore, a simple and convenient method with high sensitivity and selectivity for the determination of chitosan was established. Copyright © 2008 John Wiley & Sons, Ltd.     

Resonance light scattering study on the interaction between quinidine sulfate and congo red and its analytical application

The interaction between quinidine sulfate (QDS) and congo red (CR) was studied using resonance light scattering (RLS) technique, ultraviolet–visual spectrophotometry and fluorimetry. In weak acidic medium, QDS reacts with CR to form a supermolecular complex which results in the enhanced RLS intensity. Some important interacting parameters, such as the solution acidity and CR concentration, salt effect and addition order of the reagents, were investigated and optimized. Under the optimum conditions, it was found that the enhanced RLS intensity was in proportion to the concentration of QDS in the range 0.2–8.4 µg mL^?1. The corresponding detection limit was 12.0 ng mL^?1. The results showed that this new method enabled simple, sensitive and rapid determination of QDS and was used for the determination of QDS in urine and simulated huamn serum samples. Copyright © 2009 John Wiley & Sons, Ltd.     

Determination of proteins with fullerol by a resonance light scattering technique

Fullerol has been synthesized through the reaction of fullerene C60 with NaOH in aqueous solution by means of ultrasonic agitation and characterized by infrared and 1H-nuclear magnetic resonance spectroscopy. The fullerol obtained shows good solubility and excellent stability in water. A weak resonance light scattering (RLS) spectrum of fullerol was observed in aqueous solution. However, the intensity of the RLS signal could be enhanced in the presence of proteins, including bovine serum albumin (BSA), human serum albumin (HSA), pepsin (Pep), and lysozyme (Lys). Based on the enhancement of the RLS, a sensitive method for the determination of proteins has been established. The quantitative conditions were considered with regard to the effects of the pH, the ion strength, and the concentration of the fullerol. Under the optimum conditions, the intensity of the RLS was proportional to the concentration of proteins with the limits of detection of 9.7, 10.9, 57.4, and 8.5 ng mL(-1) for BSA, HSA, Pep, and Lys, respectively. Almost no interference can be observed from some amino acids, nucleic acids, and most of the metal ions. The model samples and human serum samples were determined satisfactorily with the proposed method.     

Degradation of polychlorinated biphenyls by extracellular enzymes of Phanerochaete chrysosporium produced in a perforated plate bioreactor

The white rot fungus Phanerochaete chrysosporium was cultivated in a perforated plate bioreactor and the expression of activities of manganese-dependent peroxidase (MnP) and lignin peroxidase (LiP) was measured. Peak activities of the two enzymes were reached close to day 11 and therefore the cultivation was terminated on that day. Extracellular proteins were concentrated and both peroxidases separated by isoelectric focusing. Degradation of technical PCB mixtures containing low and highly chlorinated congeners (Delor 103 and Delor 106 as equivalents of Aroclor 1242 and Aroclor 1260, respectively) was performed using intact mycelium, crude extracellular liquid and enriched MnP and LiP. A decrease in PCB concentration caused by a 44-h treatment with mycelium (74% w/w for Delor 103 and 73% for Delor 106) or crude extracellular liquid (62% for Delor 103 and 58% for Delor 106) was observed. The degradation was not substrate-specific, because no significant differences between the respective degradation rates were observed with di-, tri-, tetra-, penta-, hexa-, hepta-, and octachlorinated congeners. In contrast, MnP and LiP isolated from the above-mentioned extracellular liquid did not catalyse any degradation.     

Aerobic degradation of polychlorinated biphenyls by Alcaligenes sp. JB1: metabolites and enzymes

In contrast to the degradation of penta-and hexachlorobiphenyls in chemostat cultures, the metabolism of PCBs by Alcaligenes sp. JB1 was shown to be restricted to PCBs with up to four chlorine substituents in resting-cell assays. Among these, the PCB congeners containing ortho chlorine substituents on both phenyl rings were found to be least degraded. Monochloro-benzoates and dichlorobenzoates were detected as metabolites. Resting cell assays with chlorobenzoates showed that JB1 could metabolize all three monochlorobenzoates and dichlorobenzoates containing only meta and para chlorine substituents, but not dichlorobenzoates possessing an ortho chlorine substituent. In enzyme activity assays, meta cleaving 2,3-dihydroxybiphenyl 1,2-dioxygenase and catechol 2,3-dioxygenase activities were constitutive, whereas benzoate dioxygenase and ortho cleaving catechol 1,2-dioxygenase activities were induced by their substrates. No activity was found for pyrocatechase II, the enzyme that is specific for chlorocatechols. The data suggest that complete mineralization of PCBs with three or more chlorine substituents by Alcaligenes sp. JB1 is unlikely.Abbreviations PCB polychlorinated biphenyls - CBA chlorobenzoate - D di - Tr tri - Te tetra - Pe penta- - H hexa     

Determination of propafenone hydrochloride by flow‐injection analysis coupled with resonance light scattering detection

A simple, sensitive and rapid flow injection analysis (FIA) method with resonance light scattering (RLS) was described for the determination of propafenone (PPF). The method was based on the ion‐association reaction of 12‐tungstophosphoric acid (TP) with propafenone. In pH 1.0 acidic medium, TP reacted with PPF to form an ion‐associate complex, which resulted in a significant enhancement of RLS intensity. The maximum scattering peak was located at 340 nm, the RLS intensity was proportional to the concentration of PPF in the range 0.003–9.0 µg/mL, and the detection limit (3σ) of 1.0 ng/mL was obtained at a sampling rate of 60 samples/h. The feasible reaction conditions and FIA parameters for the system were optimized. The method proposed in this paper shows satisfactory reproducibility with a relative standard deviation (RSD) of 2.1% for 10 successive determinations of 2.0 µg/mL PPF. The present method had been successfully applied to the determination of PPF in serum samples and pharmaceutical samples. The results obtained were in agreement with the method used in the Chinese Pharmacopoeia. Copyright © 2008 John Wiley & Sons, Ltd.     

Resonance Rayleigh scattering methods for the determination of chitosan with Congo red as probe

Two methods were presented for the sensitive and selective determination of chitosan (CTS) with Congo red (CR) as probe based on resonance Rayleigh scattering (RRS) intensities in health products. In weakly acidic buffer solution, the binding of CTS to CR, could result in the enhancement of the RRS intensities. Moreover, after adding OP emulsifier (octyl‐phenyl polyoxyethylene ether) to the system, the RRS intensities showed more significantly enhancement. The maximum RRS signals for the CTS–CR system and the CTS–CR–OP system were located at 380 nm and 376 nm, respectively. Under optimum experimental conditions, the increased RRS intensities (ΔI) of these two systems were linear to CTS concentration in the range of 0.40–8.00 μg/ml and 0.05–1.00 μg/ml. Their limits of detection (LOD) were 44.81 ng/ml and 6.99 ng/ml, which indicated that the latter system was more sensitive than the former. In this work, the optimum conditions and the effects of some foreign substances on the determination were studied. In addition, the effect of the molecular weight of CTS and the reasons for the enhancement of resonance light scattering were discussed. Finally, these two methods were applied to the determination of chitosan in health products with satisfactory results.     

Determination of the rotational barriers of atropisomeric polychlorinated biphenyls (PCBs) by a novel stopped-flow multidimensional gas chromatographic technique

The rotational barriers ΔG^‡ (T) of the four atropisomeric polychlorinated biphenyls (PCBs) 2,2′,3,5′,6-pentachlorobiphenyl (PCB 95), 2,2′3,3′,4,6′-hexachlorobiphenyl (PCB 132), 2,2′,3,3′,6,6′-hexachlorobiphenyl (PCB 136), and 2,2′,3,4′,5′,6-hexachlorobiphenyl (PCB 149) were determined via on-line enantiomerization kinetics by a new stopped-flow multidimensional gas chromatographic technique (stopped-flow MDGC) employing Chirasil-Dex as chiral stationary phase for enantiomer separation. The calculated rotational barriers ΔG^‡ (T) of the trichloro-ortho-substituted atropisomers are 184 ± 2 kJ/mol for PCB 95, 189 ± 4 kJ/mol for PCB 132, and 184 ± 1 kJ/mol for PCB 149 at 300°C. The rotational barrier ΔG^‡ (T) of tetrachloro-ortho-substituted PCB 136 is at least (or higher than) 210 kJ/mol at 320°C. Chirality 10:316–320, 1998. © 1998 Wiley-Liss, Inc.