Biomedical subjects

Jinghe Yang

Publications and source records attributed to Jinghe Yang.

At least 19 recordsLinked to original sources

PubMed2006

Investigation of the interaction between curcumin and nucleic acids in the presence of CTAB.

It is found that nucleic acid can enhance the resonance light scattering (RLS) enhancement effect of curcumin (CU) in the presence of cationic surfactant cetyltrimethylammonium bromide (CTAB). The investigation indicates that in BR (pH 4.3) buffer, both the positive CTAB and negative yeast RNA (yRNA) combine and form a positive large association, then which is bound on the two carbon atoms of the carbonyls of CU through hydrogen bond and hydrophobic force and form CU-CTAB-yRNA ternary complex, resulting in the RLS enhancement of this system. Based on it, a sensitive method for determination of nucleic acids at ngml(-1) is established.

Cetrimonium↗

PubMed2006

Scopoletine as fluorescence probe for determination of protein.

Scopoletine (SLT), 7-hydroxy-6-methoxylcoumarin, is known to possess biological activities such as abirritating and anti-tumor, it can quench intrinsic fluorescence of bovine serum albumin (BSA) and the fluorescence intensity of itself is enhanced. So, SLT is used as fluorescence probe for quantitative determination of protein. The experiments indicate that under optimum conditions, the enhanced intensity of fluorescence is in proportion to the concentration of proteins in a wide range, and their detection limits (S/N=3) are 1.4 x 10(-8)g mL(-1) for BSA and 1.1 x 10(-8)g mL(-1) for HSA, respectively. Samples were satisfactorily determined. The interaction mechanism is also discussed.

Animals↗

PubMed2006

Fluorescence enhancement of yttrium(III)-rutin by nucleic acids in the presence of cetyltrimethylammonium bromide.

It is found that nucleic acids can enhance the fluorescence intensity of yttrium(III) (Y(3+))-rutin in presence of cetyltrimethylammonium bromide (CTMAB) system. In hexamethylenetetramine (HMTA)-HCl buffer, the maximum enhanced fluorescence is produced, with maximum excitation and emission wavelengths at 452 and 520 nm, respectively. Based on this, a new fluorimetric method of determination of nucleic acids is proposed. Under optimum conditions, the enhanced fluorescence intensity is proportion to the concentration of nucleic acids in the range of 1.0 x 10(-7) to 1.0 x 10(-5)g/ml for fish sperm DNA (fsDNA), 1.0 x 10(-7) to 4.6 x 10(-6)g/ml for yeast RNA (yRNA), their detection limits (S/N=3) are 7.5 x 10(-8), 8.0 x 10(-8)g/ml, respectively. The interaction mechanism is also studied.

Animals↗

PubMed2006

Fluorescence enhancement of the protein-curcumin-sodium dodecyl benzene sulfonate system and protein determination.

Protein can greatly enhance the fluorescence of curcumin (CU) in the presence of sodium dodecyl benzene sulfonate (SDBS). Experiments indicate that under the optimum conditions, the enhanced intensity of fluorescence is proportional to the concentration of proteins in the range of 0.0050-20.0 microg mL(-1) for bovine serum albumin (BSA), 0.080-20.0 microg mL(-1) for human serum albumin (HSA), and 0.040-28.0 microg mL(-1) for egg albumin (EA). Their detection limits (S/N = 3) are 1.4 ng mL(-1), 20 ng mL(-1), and 16 ng mL(-1), respectively. The method has been satisfactorily used for the determination of proteins in actual samples. In comparison with most of fluorimetric methods, this method is quick and simple, has high sensitivity and good stability. The interaction mechanism is also studied.

Albumins↗

PubMed2006

Flow injection-chemiluminescence determination of phenol using potassium permanganate and formaldehyde system.

It is found that phenol can react with potassium permanganate in the acidic medium and produce chemiluminescence, which is greatly enhanced by formaldehyde. The optimum conditions for this chemiluminescent reaction are in detail studied using a flow injection system. The experiments indicate that under optimum conditions, the chemiluminescence intensity is linearly related to the concentration of phenol in the range 5.0x10(-9) to 1.0x10(-6)gmL-1 with a detection limit (3sigma) of 3x10(-9)gmL-1. The relative standard deviation is 1.2% for 4.0x10(-7)gmL-1 phenol solution in 11 repeated measurements. This method has the advantages of simple operation, fast response and high sensitivity. The method is successfully applied to the determination of phenol in the waste water.

Flow Injection Analysis↗

PubMed2006

Study on the formation and depolymerization of acridine orange dimer in acridine orange-sodium dodecyl benzene sulfonate-protein system.

Experiment indicates that the fluorescence of acridine orange (AO) can be greatly quenched by anionic surfactant sodium dodecyl benzene sulfonate (SDBS), but when protein is added into the AO-SDBS system, the fluorescence intensity of the latter is enhanced. It is considered that SDBS can promote the formation of AO dimer, resulting in the quenching of the fluorescence of AO. When bovine serum albumin (BSA) is added into AO-SDBS system, BSA and SDBS can interact and form negative micelle-like cluster complex with "aromatic ring stacking," which destroys the formation conditions of AO dimer and makes some AO dimers turn into monomer, resulting in the fluorescence enhancement of AO-SDBS system. Whereas the positive AO and residual AO dimer are dissolved in the negative BSA-SDBS cluster through electrostatic and hydrophobic forces and form a large association. Here, the fluorescence enhancement of AO-SDBS is considered to originate from the hydrophobic microenvironment provided by BSA and SDBS, the depolymerization of AO dimer and intermolecular energy transfer between BSA and AO.

Acridine Orange↗

PubMed2006

The sensitive fluorimetric method for the determination of curcumin using the enhancement of mixed micelle.

Curcumin (C21H20O6) is a natural antioxidant, which is considered to be a very useful compound in health matters, and is employed in the treatment of cardiovascular and arthritic illnesses. It is found that the fluorescence of curcumin is greatly enhanced by mixed micelle of sodium dodecyl benzene sulfonate (SDBS) and cetyltrimethylammonium bromide (CTAB) surfactants. Based on this, a sensitive fluorimetric method for the determination of curcumin in aqueous solution is proposed. In the HOAc-NaOAc buffer, the fluorescence intensity of curcumin is proportional to the concentration of curcumin in the range of 0.00020-0.74 microg/mL and the detection limit is 0.017 ng/mL. The synthetic and actual samples are satisfactorily determined. In addition, the interaction mechanism is also studied.

Acetates↗

PubMed2006

The sensitive determination of nucleic acids using resonance light scattering quenching method.

It is found that in hexamethylene tetramine (HMTA)-HCl buffer of pH 7.00, nucleic acids can quench the resonance light scattering (RLS) of europium (III) (Eu3+)-2-thenoyltrifluoroacetne (TTA)-1,10-phenanthroline (Phen) system. Based on this, a sensitive method for the determination of nucleic acids is proposed. The experiments indicate that under the optimum conditions, the quenched RLS intensity is in proportion to the concentration of nucleic acids in the range of 1.0x10(-10) to 2.0x10(-6) g ml-1 for fish sperm (fsDNA), 1.0x10(-11) to 1.0x10(-6) g ml-1 for yeast RNA (yRNA), 5.0x10(-11) to 5.0x10(-7) g ml-1 for calf thymus DNA (ctDNA). Their detection limits (S/N=3) are 0.03, 0.006 and 0.002 ng ml-1, respectively. Therefore, the proposed method is the most sensitive RLS method for the determination of nucleic acids so far. The interaction between nucleic acids and Eu3+-TTA-Phen is also discussed.

Europium↗

PubMed2005

Molecular self-assembling and the fluorescence enhancement in morin-Al3+-cetyltrimethylammonium bromide-protein system.

Fluorescence enhancement effect of the morin-Al3+-cetyltrimethylammonium bromide (CTAB)-bovine serum albumin (BSA) system is reported here and the interaction mechanism is studied using fluorescence, resonance light scattering (RLS), absorption spectroscopy, Far-UV circular dichroism (CD) spectrum and small angle X-ray scattering (SAXS) measurement. It is considered that protein can bind with Al3+, morin and CTAB through self-assembling function with electrostatic attraction, hydrogen bond, hydrophobic interaction and Vander Waal force etc, and forms a supermolecular association with multilayer structure, in which morin-Al3+ is clamped between BSA and CTAB. In this system, the fluorescence enhancement of morin originates from both intermolecular energy transfer between BSA and morin, and the hydrophobic microenvironment provided by BSA and CTAB. Whereas Al3+ plays a key role for the enhancement of energy transfer efficiency because it provides an efficient channel for the energy transfer between BSA and morin.

Aluminum Compounds↗

PubMed2005

The fluorescence characteristic of the yttrium-norfloxacin system and its analytical application.

In this paper, a simple, rapid and sensitive spectrofluorimetric method based on the formation of yttrium complexes has been developed for the determination of norfloxacin (NFLX). The affecting factors of the enhancement were studied in detail. Under optimum conditions, a linear relationship was obtained between the enhanced fluorescence intensity and the NFLX concentration in the range 1.0 x 10(-9) to 1.0 x 10(-5)mol/l and the detection limit of NFLX was 3.8 x 10(-11)mol/l (S/N=3). The method is applied for the determination of NFLX in actual sample (norfloxcain eye drops), the average recovery is 102.4% (n=5), and the result obtained is satisfactory.

Buffers↗

PubMed2005

Study on the interaction between nucleic acid and Eu3+-oxolinic acid and the determination of nucleic acid using the resonance light scattering technique.

At pH 9.75, the resonance light scattering (RLS) intensity of OA-Eu3+ system is greatly enhanced by nucleic acid. Based on this phenomenon, a new quantitative method for nucleic acid in aqueous solution has been developed. Under the optimum condition, the enhanced RLS is proportional to the concentration of nucleic acid in the range of 1.0x10(-9) to 1.0x10(-6)g/ml for herring sperm DNA, 8.0x10(-10) to 1.0x10(-6) g/ml for calf thymus DNA and 1.0x10(-9) to 1.0x10(-6) g/ml for yeast RNA, and their detection limits are 0.020, 0.011 and 0.010 ng/ml, respectively. Synthetic samples and actual samples were satisfactorily determined. In addition, the interaction mechanism between nucleic acid and OA-Eu3+ is also investigated.

DNA↗

PubMed2005

Unfolding and refolding of bovine serum albumin induced by cetylpyridinium bromide.

The interaction of bovine serum albumin (BSA) with cationic surfactant cetylpyridinium bromide (CPB) in aqueous solution (pH 7.00) was studied quantitatively with ultraviolet (UV)-visible, far-UV, and near-UV circular dichroism, fluorescence, small angle x-ray scattering, and nuclear magnetic resonance measurement. It was found that CPB at low and high concentrations could induce the unfolding and refolding of BSA, respectively. We suggest that in the unfolding process, there existed BSA-CPB complex with the "necklace and bead" structure in which the unfolded BSA wrapped around CPB micelles, and that the hydrophobic interaction between the complexes led to the formation of large aggregates. The aromatic headgroup of CPB interacted with the tryptophan residues of BSA, resulting in the aromatic ring stacking between BSA and CPB. During the refolding process, the BSA molecule was penetrated into the rod micelle of CPB and the hydrophobic moiety of the BSA molecule was exposed outside while its hydrophilic part was hidden inside, thereby disrupting the aromatic ring stacking.

Animals↗

PubMed2005

Determination of nucleic acids at nanogram level using resonance light scattering technique with Congo Red.

Based on the enhancement of the resonance light scattering (RLS) of Congo Red (CR) by nucleic acid, a new quantitative method for nucleic acid is developed. In the Tris-HCl buffer (pH 10.5), the weak light scattering of CR is greatly enhanced by addition of nucleic acid and CTMAB, the maximum peak is at 560 nm and the enhanced intensity of RLS is in proportion to the concentration of nucleic acid. The linear range is 1.0 x 10(-9) to 1.0 x 10(-6) g ml(-1), 7.5 x 10(-8) to 1.0 x 10(-6) g ml(-1) and 7.5 x 10(-8) to 2.5 x 10(-6) g ml(-1) for herring sperm DNA, calf thymus DNA and yeast RNA, and the detection limits are 0.019, 0.89 and 1.2 ng ml(-1) (S/N = 3), respectively. Actual biological samples were satisfactorily determined.

Animals↗

PubMed2005

A sensitive fluorimetric method for the determination of epinephrine.

A sensitive fluorimetric method for the determination of epinephrine (E) is described in this paper. The experiments indicate that epinephrine can react with formaldehyde (HCHO) in an acid medium to form a condensation product, which can be oxidized by potassium hexacyanoferrate(III) (K3[Fe(CN)6]) in borax buffer (pH = 9.5). The reaction product can emit strong fluorescence. Ascorbic acid (AA) is used in order to consume excess potassium hexacyanoferrate and stabilize the fluorescent product. Under optimum conditions, a linear relationship has been obtained between the fluorescence intensity and the concentration of epinephrine in the range of 1.4 x 10(-9) - 2.1 x 10(-6) mol/l, and the detection limit is 2.4 x 10(-10) mol/l (4.3 x 10(-11) g/ml, S/N = 3). The method is applied for the determination of E in both actual sample and the synthetic sample with E and norepinephrine (NE) by using the coupling technique of synchronous fluorimetry and H-point standard addition method, and the results obtained are satisfactory.

Ascorbic Acid↗

PubMed2005

The sensitive determination of nucleic acids using fluorescence enhancement of Eu3+-benzoylacetone-cetyltrimethylammonium bromide-nucleic acid system.

A new quantitative method for micro amounts of nucleic acids in aqueous solution is proposed using Eu3+-benzoylacetone (BA) complex as fluorescent probe in the presence of cetyltrimethyl-ammonium bromide (CTMAB). Under the optimum condition, the ratio of the fluorescence intensities with and without nucleic acids is proportional to the concentration of nucleic acid in the range of 1.0x10(-9) to 5.0x10(-6) g/mL for herring sperm DNA (hsDNA), 3.0x10(-9) to 1.0x10(-6) g/mL for calf thymus DNA(ctDNA) and 8.0x10(-9) to 1.0x10(-6) g/mL for yeast RNA (yRNA), and their detection limits are 0.33, 0.21 and 0.99 ng/mL, respectively. Actual sample (DNA of Arabidopsis thaliana) was determined satisfactorily. In addition, the interaction mechanism is also investigated.

Arabidopsis↗

PubMed2005

Resonance light scattering technique for the determination of protein with rutin and cetylpyridine bromide system.

A new resonance light scattering (RLS) assay of protein is presented. In Tris-NaOH (pH = 10.93) buffer, the RLS of rutin-cetylpyridine bromide (CPB) system can be greatly enhanced by protein, including bovine serum albumin (BSA) and human serum albumin (HSA). The enhanced RLS intensities are in proportion to the concentration of proteins in the range of 5 x 10(-9) to 2.5 x 10(-6) g ml(-1) for BSA and 2.5 x 10(-8) to 3.5 x 10(-6) g ml(-1) for HSA. The detection limits (S/N = 3) are 3.0 ng ml(-1) for BSA and 10.0 ng ml(-1) for HSA. Samples are determined satisfactorily.

Animals↗

PubMed2004

Study of the interaction of proteins with curcumin and SDS and its analytical application.

It is found that protein and sodium dodecyl sulphonate (SDS) can enhance resonance light scattering (RLS) of curcumin (CU). Based on this phenomenon, a new quantitative method for protein in aqueous solution has been developed. In the BR (pH 3.5) buffer, the RLS intensity of CU-SDS system is greatly enhanced by protein. The enhanced RLS is proportional to the concentration of protein in the range of 0.00020-20.0 microgml(-1) for bovine serum albumin (BSA) and 0.00040-1.0 microgml(-1) for human serum albumin (HSA) and their detection limits are 0.16 and 0.041 ngml(-1), respectively. An actual sample is satisfactorily determined. In addition, the interaction mechanism between protein and CU-SDS is also studied by using multi-techniques such as RLS, absorption spectroscopy and fluorescence, zeta potential assay measurement.

Animals↗

PubMed2004

The fluorescence enhancement effect of the Tb-Gd-guanosine-5'-triphosphate-phen system and its analytical application.

It has been found that Tb(3+) can react with guanosine-5'-triphosphate (GTP) and o-phenanthroline (phen), resulting in the intrinsic fluorescence of Tb(3+). This fluorescence can be enhanced by adding La(3+), Gd(3+), Lu(3+), Sc(3+), Y(3+), and so on, among which Gd(3+) produces the greatest enhancement. These are new co-luminescence systems. The experiments indicate under optimum conditions, the fluorescence intensity of the Tb-Gd-GTP-phen system is proportional to the concentration of GTP over the range 1x10(-9) to 3x10(-5) mol/l. The detection limit is 3.1x10(-10) mol/l. The proposed method provides the most sensitive fluorimetry of GTP so far. The mechanism of the Tb-Gd-GTP-phen system has also been studied. The data indicates that there is a large congeries of Tb-Gd-GTP-phen, and the fluorescence enhancement of the Tb-Gd-GTP-phen system is considered to originate from intramolecular and intermocular energy transfers, and the energy-insulating sheath of the Gd complex.

Gadolinium↗