Biomedical subjects

Rong-qiao He

Publications and source records attributed to Rong-qiao He.

4 recordsLinked to original sources

PubMed2004

Neuronal tau induces DNA conformational changes observed by atomic force microscopy.

Neuronal tau associates with chromosome scaffold and localizes in the nuclear and the nucleolar organization regions in neuronal and some non-neuronal cells. Observing the interaction of neuronal tau with DNA under AFM shows that tau binds to DNA as a monomer, and tau-DNA complex forms a beads-on-a-string structure when the mass ratio is 1:10 (molar ratio of tau/DNA approximately 1:700 bp). A beads-on-a-coil structure, in which tau is as polymers, will appear when the mass ratio is up to 1:5 (molar ratio of tau/DNA approximately 1:350 bp). The present observation that neuronal tau bends the DNA double strands indicates that the appearance of the tau-DNA complex is dependent upon the mass (or molar) ratio of tau and DNA.

DNA↗

PubMed2003

Tau could protect DNA double helix structure.

The hyperchromic effect has been used to detect the effect of tau on the transition of double-stranded DNA to single-stranded DNA. It was shown that tau increased the melting temperature of calf thymus DNA from 67 to 81 degrees C and that of plasmid from 75 to 85 degrees C. Kinetically, rates of increase in absorbance at 260 nm of DNA incubated with tau were markedly slower than those of DNA and DNA/bovine serum albumin used as controls during thermal denaturation. In contrast, rates of decrease in the DNA absorbance with tau were faster than those of controls when samples were immediately transferred from thermal conditions to room temperature. It revealed that tau prevented DNA from thermal denaturation, and improved renaturation of DNA. Circular dichroic spectra results indicated that there were little detectable conformational changes in DNA double helix when tau was added. Furthermore, tau showed its ability to protect DNA from hydroxyl radical (.OH) attacking in vitro, implying that tau functions as a DNA-protecting molecule to the radical.

Animals↗

PubMed2002

A convenient assay of glycoserum by nitroblue tetrazolium with iodoacetamide.

BACKGROUND: To determine glycoserum, the nitroblue tetrazolium (NBT) assay is quick, economical, convenient and easily automated. This method, however, is vulnerable to interference by thiol group, which should not be ignored during the analysis. METHODS: Thiol group in glycoserum was blocked with iodoacetamide (IAM) before NBT was added. The reaction was carried out in a thermal bath and terminated on ice. The absorbance was measured at either 570 or 530 nm. RESULTS: IAM (3-10 mmol/l) did not give any detectable interference in the NBT assay. The absorbance at both 570 and 530 nm was linearly related to the concentration of either glycoserum or 1-deoxy-1-morpholino-D-fructose (DMF) that had been treated with IAM. The assay showed a good discrimination between diabetic and normal subjects (t-test, P < 0.001). Uric acid and lipemia under physiological conditions did not interfere with NBT reaction. The assay was affected by hyperlipemia and hematolysis. CONCLUSIONS: IAM-modified method prevented NBT assay from the interference by thiol group and uric acid.

Blood Glucose↗

PubMed2002

Immobilized earthworm fibrinolytic enzyme III-1 with carbonyldiimidazole activated-agarose.

Earthworm fibrinolytic enzyme III-1 (EFE-III-1) was prepared to couple with cross-linking agarose activated by 1,'-Carbonyl- diimidazole (CDI) in this study. Although the activity of the immobilized protease decreased to approximately 64% of the native enzyme, the activity of EFE-III-1 coupled with the resin activated by CDI was higher than that activated by cyanogen bromide (CNBr). The immobilized protease was experimentally demonstrated to hydrolyze IgG, albumin and creatine kinase, besides fibrin(ogen) and plasmin(ogen), suggesting that EFE had a broad substrate specificity.

Animals↗