Structure and antioxidant activity of polysaccharide POJ-U1a extracted by ultrasound from Ophiopogon japonicus.

An ultrasonic technique was employed to extract polysaccharides from Ophiopogon japonicus. The ultrasonic extracted polysaccharides (POJ-U) were purified, and POJ-U1a (a homogeneous fraction) was obtained. The structural characteristics of POJ-U1a were investigated by infrared spectra, gas chromatography, high performance liquid chromatography, periodate oxidation, Smith degradation, methylation analysis, gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy. The results indicated that the relative molecular weight of POJ-U1a was 4.02×10(3)Da. POJ-U1a was an α-configuration polysaccharide with a highly branched structure, and consisted of pyranoside and funanside. The backbone of POJ-U1a consisted of 1,6-α-d-glucopyranose and 1,3,6-α-d-glucofuranose in the molar ratio of 7:3, while the branched chains were mainly composed of 1,3-α-d-glucopyranose and 1-α-d-glucopyranose in the molar ratio of 1:3. The branched structure of POJ-U1a was proved intuitively by AFM. Significant antioxidant activity of POJ-U1a has been proved as shown by its DPPH radical scavenging, hydrogen radical scavenging and superoxide anion scavenging activities, which indicated that POJ-U1a showed strong antioxidant activity.

Biologic effects of SMF and paclitaxel on K562 human leukemia cells.

In this study, we evaluated the ability of 8.8 mT static magnetic fields (SMF) to enhance the in vitro action of a chemotherapeutic agent, paclitaxel, against K562 human leukemia cells. We analyzed the cell proliferation, cell cycle distribution, DNA damage and alteration of cell surface and cell organelle ultrastructure after K562 cells were exposed to paclitaxel in the presence or absence of 8.8 mT SMF. The results showed that in the presence of SMF, the efficient concentration of paclitaxel on K562 cells was decreased from 50 to 10 ng/ml. Cell cycle analysis indicated that K562 cells treated with SMF plus paclitaxel were arrested at the G2 phase, which was mainly induced by paclitaxel. Through comet assay, we found that the cell cycle arrest effect of paclitaxel with or without SMF on K562 cells was correlated with DNA damage. The results of atomic force microscopy and transmission electron microscopy observation showed that the cell ultrastructure was altered in the group treated with the combination of SMF and paclitaxel, holes and protuberances were observed, and vacuoles in cytoplasm were augmented. Our data indicated that the potency of the combination of SMF and paclitaxel was greater than that of SMF or paclitaxel alone on K562 cells, and these effects were correlated with DNA damage induced by SMF and paclitaxel. Therefore, the alteration of cell membrane permeability may be one important mechanism underlying the effects of SMF and paclitaxel on K562 cells.

An investigation into the combined effect of static magnetic fields and different anticancer drugs on K562 cell membranes.

AIMS AND BACKGROUND: Cell membranes were shown to be sensitive to and affected by static magnetic fields (SMF). METHODS: Cells were treated with four anticancer drugs followed by treatment with a combination of drugs and SMF. Individual cells were examined using atomic force microscopy (AFM). The drugs were taxol (alkaloid), doxorubicin (anthracycline), cisplatin (platinum compound) and cyclophosphamide (alkylating agent). RESULTS: Holes were observed in cells exposed to SMF but not in control groups. The number, size and shape of the holes were dependent on the drug type, SMF parameters and the duration of exposure. CONCLUSIONS: The results suggest that the application of a SMF could alter membrane permeability, increasing the flow of the anticancer drugs. This may be one of the reasons why SMF can strengthen the effect of anticancer drugs. Observations were also made of the effect of using different anticancer drugs. For example, the effect of SMF combined with taxol or cyclophosphamide on the cells was additive while the effect of SMF combined with cisplatin or doxorubicin was synergistic. The target sites of cisplatin and doxorubicin are nucleic acids; continued research is required into this important area to ascertain the effect of SMF on nucleic acids.

Static magnetic fields enhanced the potency of cisplatin on k562 cells.

PURPOSE: This study investigates whether 8.8 mT static magnetic fields (SMFs) can enhance the killing potency of cisplatin (DDP) on human leukemic cells (K562). METHODS: The cell proliferation, cell cycle distribution, DNA damage, and the change in cell surface ultrastructure after K562 cells were exposed to 8.8 mT SMFs with or without DDP were analyzed. RESULTS: The results show that SMFs enhanced the killing effect of DDP on K562 cells, reducing the efficient killing concentration of DDP on K562 cells from 20 to 10 microg/mL. Atomic force microscope observation showed that the cell surface ultrastructure was altered. The results of fluorescence-activated cell sorting analysis indicated that K562 cells treated with SMF plus DDP were arrested at the S phase. The SMF exposure induced DNA to become thicker than controls, and breakage of DNA occurred in the DDP group; however, DNA breakage was increased in the SMF + DDP group. CONCLUSIONS: The results show that SMFs enhanced the anticancer effect of DDP on K562 cells. The mechanism correlated with the DNA damage model. This study also shows the potentiality of SMFs as an adjunctive treatment method for chemotherapy.

[Laser Raman and infrared spectrum analysis of low-density lipoproteins purified from hen egg yolk].

During the experiment, diversified proteins were separated from hen egg yolk by ammonium sulphate rapid fractionation, and pure LDL was obtained after filtrating through Sephadex G-200 chromatography. After the qualitative detection of SDS-PAGE, the authors discovered that LDL consists of five major apoprotein. The Raman and infrared spectrum showed CH2 asymmetric stretching and symmetric stretching mode. However, the authors found C==O stretching vibrations of protein peptide bonds and N+ (CH3)3 asymmetric stretching vibration from the choline group in phospholipids. Laser Raman and infrared spectrum analysis of LDL provided useful information for studying their structure.

[IR/UV spectroscopic analysis of gangliosides and their microstructures of polymeric aggregates observed by AFM technique].

Gangliosides, a kind of acid glycosphingolipid containing sialic acid, plays a very important physiological role in biomembrane as one of the important components of neurocyte membrane. They were extracted from bovine brain by the Folch method and purified by silica gel and DEAE-Sephadex A-25 column chromatograph. Their molecular functional groups and microstructures of polymeric aggregates were studied by infrared spectrum (IR), ultraviolet spectrum (UV) and atomic force microscope (AFM). The experimental results indicate that: 55.2 mg of Gls from 100 g of wet bovine brain had a certain purity, 62.84%. And their UV absorption spectra appeared at 195 nm, near to the results reported by other peoples. Compared with the IR spectra of sialic acid, the experimental results showed that the structures of the products had the units of sialic acid. In order to investigate the aggregate structures of ganglioside. AFM technique was applied in water, and the results showed that gangliosides can form spherical or ellipsoidal structures in water. It was determined that the size of polymeric aggregates of gangliosides varies between 55 and 380 nm, the average size is (148.9+/-66.7) nm; the height is between 1.0 and 5.0 nm, and the average height is (3.25+/-1.01) nm. The experimental results provide a theoretical and experimental basis for investigating biological activity and the exploitation and utilization of neural drugs.

[Characterization of structure of carboxymethylpachymaran by IR spectrum and atomic force microscopy].

The structure of Carboxymethylpachymaran was characterized using Fourier transform infrared spectroscopy. Morphological changes of carboxymethylpachymaran (CMP) were observed under different solution conditions by atomic force microscopy (AFM). After the carboxymethylation, the solubility of pachyman in the water was significantly increased, its beta-D-glucan characteristic absorption peak at 890 cm(-1) became weak obviously, and its methylene vibration absorption peak and C = O antisymmetrical stretch vibration absorption peak appeared at 1,333 and 1,606 cm(-1) respectively, which indicated that the carboxymethylation succeeded. The analysis of AFM results showed that CMP molecules existed in different morphology under different solution conditions, and that the concentration, ionic strength and solvent physical chemistry characteristics of polysaccharide solution had effects on the CMP chains conformation and the action mode between different molecular chains. The phenomena were considered to be related to hydrogen bond association and intramolecular and intermolecular electrostatic interactions of CMP. Meanwhile, the affinity and electrostatic interaction between CMP molecules and the mica substrate also had an influence on the CMP chains conformation and the image quality.

[Surface enhanced Raman scattering spectra of carbozole and azobenzene disperse red polymer].

Surface enhanced resonance Raman scattering (SERRS) was employed to study the molecule alignment of carbozole and azobenzene disperse red polymer on the surface of rough silver thin film. According to the selection rule of optical transitions and experiment results, it was found that the surface geometry of carbozole and azobenzene disperse red polymer was: this was physical adsorption between the carbazole group, which is from the monomer of carbazole and nitro-group which is from the monomer of azobenzene on the surface of rough silver film, and there is almost no interaction between the principal chain and the substrate because of the distance. This geometrical configuration of CAP on the surface of the substrate was proposed to damage the stabilities and efficiency of azobenzene derivatives based optical storage devices.

[Multiple emissions in organic electroluminescent device using a mixed layer as an emitter].

A organic electroluminescent device has been fabricated by using a mixed layer as an emitter. The configuration of the device is ITO/TPD/TPD: PBD(equimole)/PBD/A1, in which TPD (N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine) and PBD (2-(4'-biphenyl)-5-(4''-tert-butylphenyl)-1,3,4-oxadiazole) are used as hole transport material and electron transport material, respectively. Broad and red-shifted electroluminescent spectra related to the fluorescence of constituent materials were observed. It is suggested that the monomer, exciplex and electroplex emissions are simultaneously involved in EL spectra by comparison of the EL with the PL spectra and decomposition of the EL spectrum. The type of exciplex is the interaction between the excited state TPD (TPD*) and PBD in the ground state, and the type of electroplex is a (D+-A-)* complex by cross-recombination of hole on the charged hole transport molecule (D+) and electron on the charged electron transport molecule (A-). All types of excited states show different formation mechanisms and recombination processes under electric field. The change of emission strengths from monomer and excited complexes lead to a blue-shift of the emissive spectra with an increasing electric field. The maximum luminance and external quantum efficiency of this device are 240 cd x (cm2)(-1) and 0.49%, respectively. The emissions from exciplex or electroplex formation at the organic solid interface generally present a broad and red-shifted emissive band, providing an effective method for tuning of emission color in organic electroluminescent devices.