The growth-regulating factor PdbGRF1 positively regulates the salt stress response in Populus davidiana × P. bolleana

Growth-regulating factor (GRF) is a transcription factor unique to plants that plays a crucial role in the growth, development and stress adaptation of plants. However, information on the GRFs related to salt stress in Populus davidiana × P. bolleana is lacking. In this study, we characterized the activity of PdbGRF1 in transgenic Populus davidiana × P. bolleana under salt stress. qRTPCR analyses showed that PdbGRF1 was highly expressed in young leaves and that the pattern of PdbGRF1 expression was significantly changed at most time points under salt stress, which suggests that PdbGRF1 expression may be related to the salt stress response. Moreover, PdbGRF1 overexpression enhanced tolerance to salt stress. A physiological parameter analysis showed that the overexpression of PdbGRF1 significantly decreased the contents of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) and increased the activities of antioxidant enzymes (SOD and POD) and the proline content. A molecular analysis showed that PdbGRF1 regulated the expression of PdbPOD17 and PdbAKT1 by binding to the DRE ('A/GCCGAC') in their respective promoters. Together, our results demonstrate that the binding of PdbGRF1 to DRE regulates genes related to stress tolerance and activates the associated physiological pathways, and these effects increase the ROS scavenging ability, reduce the degree of damage to the plasma membrane and ultimately enhance the salt stress response in Populus davidiana × P. bolleana.

[Study on platelet-derived growth factor mRNA and copper-zinc superoxide dismutase mRNA expression changes of aortic artery endothelium with restenosis after aortic artery dilatation treated with buyang huanwu decoction]

OBJECTIVE

To study on dynamic mechanism of restenosis after PTCA treated with Buyang Huanwu Decoction (BYHWD).

METHODS

Twenty-eight male New Zealand rabbits with mimic restenosis after aortic artery dilatation were detected by prime in situ labeling in aortic endothelium. The items included gene expression of copper zinc superoxide dismutase (SOD-1) and platelet-derived growth factor receptor (PDGFR) mRNA to analyse dynamic mechanism of restenosis.

RESULTS

Seven days after aortic artery dilatation, PDGFR mRNA of aortic endothelium decreased clearly. The comparison between experimental and the control group showed significant difference (P < 0.05). By the same condition, the gene expression of SOD-1 was increasing, which showed a significant difference with the control group (P < 0.05).

CONCLUSIONS

BYHWD increased SOD-1 gene expression of artery endothelium, to improve oxygen feed for ischemia reperfusion in the same way, BYHWD suppressed PDGFR mRNA expression to control cellular pathological proliferation.

Safety and immunogenicity of live attenuated hepatitis A virus vaccine (H2 strain) in humans

A study was made in Neijiang City, Sichuan Province to observe the safety and immunogenicity of a live attenuated hepatitis A virus (HAV) vaccine (H2 strain). 3,031 children, aged 6 to 9 years, were injected subcutaneously with 10(6.0) TCID50, 10(5.5) TCID50, and 10(5.0) TCID50 of HAV vaccine; the seroconversion rate and antibody GMT were 97.52%-90.68%, GMT = 1:5.19 +/- 1.90-1:3.36 +/- 1.94; 84.75%-76.27%, GMT = 1:4.29 +/- 1.96-1:2.0 +/- 2.67; 53.23%-51.61%, GMT = 1:2.57 +/- 1.89-1:1.68 +/- 1.41 respectively after 4 weeks to 12 months of inoculation. Forty-eight children in the control group were anti-HAV negative at 4, 8, and 12 weeks; 21 children in the oral group were not antibody positive 4 and 8 weeks after oral administration of the vaccine. The stool specimens of 3 of the 14 vaccinated children were HAA positive. The results suggest that the live attenuated HAV vaccine (H2 strain) is of good immunogenicity and safety.

Study in cytotoxicity of gentamycin to corneal epithelium and endothelium in tissue culture

A study in cytotoxicity of gentamycin to tissue-cultured bovine corneal endothelial cells and rabbit corneal epithelial cells is reported. When the cultured cells reached confluence, they were exposed to tissue culture media containing gentamycin for 6 hours. We found that 0.5% gentamycin caused significant damage to corneal epithelial cells--diffuse plasmolysis, with scattered cell necrosis and 5% loss. While corneal endothelial cells were exposed to 1.6 mg/ml gentamycin, extensive cell loss (approximately 15%) was observed. The damaged cells recovered their normal morphology after 24 hours. When the concentration of gentamycin increased twice, serious damage to cells occurred. The area of cell loss reached 40%, and the recovery of cellular morphology was much slower. This study demonstrates that gentamycin potential cytotoxicity to corneal epithelium and endothelium, suggesting that gentamycin should be rationally used in the treatment of ocular diseases.