The dual functions of WLIM1a in cell elongation and secondary wall formation in developing cotton fibers.

LIN-11, Isl1 and MEC-3 (LIM)-domain proteins play pivotal roles in a variety of cellular processes in animals, but plant LIM functions remain largely unexplored. Here, we demonstrate dual roles of the WLIM1a gene in fiber development in upland cotton (Gossypium hirsutum). WLIM1a is preferentially expressed during the elongation and secondary wall synthesis stages in developing fibers. Overexpression of WLIM1a in cotton led to significant changes in fiber length and secondary wall structure. Compared with the wild type, fibers of WLIM1a-overexpressing plants grew longer and formed a thinner and more compact secondary cell wall, which contributed to improved fiber strength and fineness. Functional studies demonstrated that (1) WLIM1a acts as an actin bundler to facilitate elongation of fiber cells and (2) WLIM1a also functions as a transcription factor to activate expression of Phe ammonia lyase-box genes involved in phenylpropanoid biosynthesis to build up the secondary cell wall. WLIM1a localizes in the cytosol and nucleus and moves into the nucleus in response to hydrogen peroxide. Taken together, these results demonstrate that WLIM1a has dual roles in cotton fiber development, elongation, and secondary wall formation. Moreover, our study shows that lignin/lignin-like phenolics may substantially affect cotton fiber quality; this finding may guide cotton breeding for improved fiber traits.

Down-regulation of GhADF1 gene expression affects cotton fibre properties.

Cotton fibre is the most important natural fibres for textile industry. To date, the mechanism that governs the development of fibre traits is largely unknown. In this study, we have characterized the function of a member of the actin depolymerizing factor (ADF) family in Gossypium hirsutum by down-regulation of the gene (designated as GhADF1) expression in the transgenic cotton plants. We observed that both the fibre length and strength of the GhADF1-underexpressing plants increased as compared to the wild-type fibre, and transgenic fibres contained more abundant F-actin filaments in the cortical region of the cells. Moreover, the secondary cell wall of the transgenic fibre appeared thicker and the cellulose content was higher than that of the control fibre. Our results suggest that organization of actin cytoskeleton regulated by actin-associated proteins such as GhADF1 plays a critical role in the processes of elongation and secondary cell wall formation during fibre development. Additionally, our study provided a candidate intrinsic gene for the improvement of fibre traits via genetic engineering.

[Contraceptive efficacy of bioadhesive benzalkonium chloride gel in comparison with nonoxynol-9 gel].

OBJECTIVE: To compare the contraceptive efficacy of a new spermicide, bioadhesive benzalkonium chloride (BZK) gel, with the traditional nonoxynol (NP-9) gel. METHODS: A total of 240 child-bearing age women volunteers were randomly divided into two groups: 120 using the BZK gel for contraception, and the other 120 using the NP-9 gel. Using life table method and log-rank test, we compared the pregnancy rates and discontinuation rates after follow-up for 6 months in two groups. RESULTS: No abnormal findings of cervical smears were detected before and after this clinical trial in all 240 women. The follow-up rates at 6 months were 100.0% and 99.2% in the BZK group and the NP-9 group, respectively. The 6-month gross cumulative pregnancy rates of typical use were 1.72 and 0.91 per 100 women (P > 0.05), respectively. If we excluded the 2 pregnant women (1 in each group), who did not correctly or consistently use the spermicides for every intercourse, the cumulative pregnancy rates at 6 months in perfect use would be 0.87 and 0 per 100 women (P > 0.05). And the gross cumulative discontinuation rates due to allergy or other adverse reactions at 6 months in typical use were 0 and 2.68 per 100 women (P > 0.05), respectively. CONCLUSION: The contraceptive efficacy of bioadhesive BZK gel is the same as that of the NP-9 gel, and it is more acceptable in clinical use.

[Pulsed Nd:YAG laser-aided debonding for removing the metal brackets].

OBJECTIVE: To explore the possibility of pulsed Nd:YAG laser-aided debonding for removing orthodontic metal brackets and to compare the method with the conventional mechanical debonding method. METHODS: Fifty healthy premolars extracted for orthodontic purpose were randomly divided into five groups (10 teeth in each group). There were four experimental groups and one control group. Every tooth was bonded with bracket. Laser was used to irradiate the teeth in experimental groups with different electric currents (13.0, 13.5, 14.0, 14.5 A). During the irradiation, the brackets received 4.9 N of force until the brackets off. The time needed for debonding and the temperature change of the pulp cavity were recorded. The teeth in control group were debonded using mechanical method. The adhesive remnant index (ARI) was calculated using stereomicroscope and imagetool software. All samples were examined with a scanning electron microscope. RESULTS: The time taken between the four groups were (67.70 ± 7.18), (35.90 ± 4.28), (24.90 ± 3.76), (6.90 ± 2.33) s, highly statistical difference was found in the time needed for debonding (P < 0.01). The temperature in the pulp cavity among the four groups were (20.97 ± 3.10), (12.75 ± 3.14), (8.99 ± 2.47), (2.91 ± 1.88)°C, and statistical differences were found in temperature change of the pulp cavity (P < 0.05). ARI of three experimental groups and the control group were (8.55 ± 5.02)%, (15.42 ± 7.37)%, (5.55 ± 3.79)%, (13.72 ± 6.69)%, and (74.36 ± 29.44)%. The enamel surface of the control group was coarse with deep scratchs. The enamel surface was smooth and clean in the experimental groups. CONCLUSIONS: Pulsed Nd:YAG laser-aided debonding for removing metal brackets was feasible. Laser-aided debonding was better than conventional mechanical debonding method. The method reduced the damage to the enamel surface.