Phytoene Synthase Gene ( PSY ) from Sweet Potato ( Ipomoea batatas Lam) Enhances Tolerance to Abiotic Stress

ABSTRACT Phytoene synthase (PSY) is the rate-limiting enzyme for carotenoid biosynthesis. To date, several studies focused on PSY genes in the context of abiotic stress responses. In this study, two phytoene synthase encoding genes, IbPSY1 and IbPSY2, were identified from a published transcriptome and bioinformatic analysis showed that they shared conserved domains with phytoene synthases from other plants. The IbPSY1 gene was cloned and carefully characterized. Digital gene expression profiling (DGE) showed that the highest transcription level of IbPSY1 was in young leaves, and the lowest level was in stems. In vivo expression levels of IbPSY1 under abiotic stress were observed to be highest in stems at day 11. Over-expression of IbPSY1 in Escherichia coli and yeast cells endowed the cells with better growth under salt and drought stress than the control cells. This study demonstrated that IbPSY1 not only played an important role in vivo, but also in E. coli and yeast to improve tolerance to salinity and drought stress. Thus, IbPSY1 may be aid in the development of transgenic plants with enhanced stress tolerance.

Mask-wearing and respiratory infection in healthcare workers in Beijing, China

OBJECTIVES: The aim of the study was to determine rates of mask-wearing, of respiratory infection and the factors associated with mask-wearing and of respiratory infection in healthcare workers (HCWs) in Beijing during the winter of 2007/2008. METHODS: We conducted a survey of 400 HCWs working in eight hospitals in Beijing by face to face interview using a standardized questionnaire. RESULTS: We found that 280/400 (70.0 percent) of HCWs were compliant with mask-wearing while in contact with patients. Respiratory infection occurred in 238/400 (59.5 percent) subjects from November, 2007 through February, 2008. Respiratory infection was higher among females (odds ratio [OR], 2.00 [95 percent confidence interval {CI}, 1.16-3.49]) and staff working in larger hospitals (OR, 1.72 [95 percent CI, 1.092.72]), but was lower among subjects with seasonal influenza vaccination (OR, 0.46 [95 percent CI, 0.280.76]), wearing medical masks (reference: cotton-yarn; OR, 0.60 [95 percent CI, 0.39-0.91]) or with good mask-wearing adherence (OR, 0.60 [95 percent CI, 0.37-0.98]). The risk of respiratory infection of HCWs working in low risk areas was similar to that of HCWs in high risk area. CONCLUSION: Our data suggest that female HCWs and staffs working in larger hospitals are the focus of prevention and control of respiratory infection in Beijing hospitals. Mask-wearing and seasonal influenza vaccination are protective for respiratory infection in HCWs; the protective efficacy of medical masks is better than that of cotton yarn ones; respiratory infection of HCWs working in low risk areas should also be given attention.

Comparison of Intraocular Pressures at Different Points in Human's Cornea before and after Laser in situ Keratomileusis with Tono-Pen Tonometer / 华中科技大学学报（医学）（英德文版）

In order to explore the difference of intraocular pressure (IOP) at different points of cornea before and after laser in situ keratomileusis (LASIK),IOP was measured by Tono-Pen Tonometer at central cornea,pericentral cornea and limbus respectively and analyzed statistically.After LASIK,IOP was dropped significantly at central cornea and pericentral cornea (P＜0.05),while no statistically significant change occurred at limbus (P＞0.05).There was no statistically significant difference in IOP at different points before LASIK (F=0.110,P=0.896),but statistically significant difference was found after LASIK (F=7.375,P=0.001).It was suggested that reliable IOP after LASIK could be obtained from the limbus by Tono-Pen tonometer.

Effect of Laser in situ Keratomileusis on Accommodation / 华中科技大学学报（医学）（英德文版）

Summary: The accommodative function before and after laser in situ keratomileusis (LASIK) was observed, and the effect of LAS IK on accommodation was investigated. In a prospective clinical trial,48 myopic patients (96 eyes) subject to bilateral LASIK in Refractive Surgery Center, Tongji Hospital, Tongii Medical College, Huazhong University of Science and Technology (China) from March 2006 to June 2006 were selected and studied. Refractions, accommodative range, amplitude of accommodative response and high frequency component (HFC) of accommodative microfluctuations were measured with NEDIK-730A before and one week and 30 days after operation. Dominant and non-dominant eyes were determined by hole-in-card method. It was found that all of the operative eyes showed an uncorrected visual acuity of 0.8 or better one week postoperatively, and 1.0 or better 30 days postoperatively. Compared with those preoperatively, accommodative range and HFC had no significant difference at first week and 30th day after operation in both dominant eyes and non-dominant eyes (P0.05), but there was a significant difference in the amplitude of accommodative response/accommodative stimulus ratio (A/S) after operation (P<0.01), and no significant difference was found in' accommodation between one week and 30 days postoperation. No ocular dominance's change was noted. There was no significant difference in accommodative function between dominant eyes and non-dominant eyes. It was suggested that LASIK produced no significant effect on accommodation.