普通小麦T型细胞质雄性不育系及其保持系线粒体多肽的电泳比较研究

应用单向SDS-PAGE和双向IEF-SDS电泳技术对两个品种的普通小麦(T.aestivum L.)T型细胞质雄性不育系及其保持系的线粒体多肽进行了比较研究,结论如下:1.黄化苗期不育系和保持系线粒体多肽在单向SDS-PAGE和双向IEF-SDS电泳行为上无明显差别;2.在孕穗期幼穗线粒体多肽的单向SDS-PAGE图谱上,两个不育系都缺少28Kd多肽带纹,因而不育系和保持系间表现出明显的差异。双向IEF-SDS凝胶电泳证实28Kd带纹实际上是分子量相同而等电点分别为5.58和5.65的两个多肽;3.线粒体基因的表达是具有时空性质的;4.线粒体与T型细胞质雄性不育可能存在着某种特定的关系。 本文还就T型细胞质雄性不育的分子机制进行了探索性讨论。     

Simultaneous silencing of VEGF and KSP by siRNA cocktail inhibits proliferation and induces apoptosis of hepatocellular carcinoma Hep3B cells

Background

Vascular endothelial growth factor (VEGF) is involved in the growth of new blood vessels that feed tumors and kinesin spindle protein (KSP) plays a critical role in mitosis involving in cell proliferation. Simultaneous silencing of VEGF and KSP, an attractive and viable approach in cancer, leads on restricting cancer progression. The purpose of this study is to examine the therapeutic potential of dual gene targeted siRNA cocktail on human hepatocellular carcinoma Hep3B cells.

Results

The predesigned siRNAs could inhibit VEGF and KSP at mRNA level. siRNA cocktail showed a further downregulation on KSP mRNA and protein levels compared to KSP-siRNA or VEGF-siRNA, but not on VEGF expression. It also exhibited greater suppression on cell proliferation as well as cell migration or invasion capabilities and induction of apoptosis in Hep3B cells than single siRNA simultaneously. This could be explained by the significant downregulation of Cyclin D1, Bcl-2 and Survivin. However, no sigificant difference in the mRNA and protein levels of ANG2, involving inhibition of angiogenesis was found in HUVECs cultured with supernatant of Hep3B cells treated with siRNA cocktail, compared to that of VEGF-siRNA.

Conclusion

Silencing of VEGF and KSP plays a key role in inhibiting cell proliferation, migration, invasion and inducing apoptosis of Hep3B cells. Simultaneous silencing of VEGF and KSP using siRNA cocktail yields promising results for eradicating hepatocellular carcinoma cells, a new direction for liver cancer treatment.     

Honeybee odometry: performance in varying natural terrain

Recent studies have shown that honeybees flying through short, narrow tunnels with visually textured walls perform waggle dances that indicate a much greater flight distance than that actually flown. These studies suggest that the bee's “odometer” is driven by the optic flow (image motion) that is experienced during flight. One might therefore expect that, when bees fly to a food source through a varying outdoor landscape, their waggle dances would depend upon the nature of the terrain experienced en route. We trained honeybees to visit feeders positioned along two routes, each 580 m long. One route was exclusively over land. The other was initially over land, then over water and, finally, again over land. Flight over water resulted in a significantly flatter slope of the waggle-duration versus distance regression, compared to flight over land. The mean visual contrast of the scenes was significantly greater over land than over water. The results reveal that, in outdoor flight, the honeybee's odometer does not run at a constant rate; rather, the rate depends upon the properties of the terrain. The bee's perception of distance flown is therefore not absolute, but scene-dependent. These findings raise important and interesting questions about how these animals navigate reliably.     

Detection of endo-xylanase activities in electrophoretic gels with congo red staining

Summary A modification of the Congo Red zymographic technique is used to analyse multiple xylanase activities of Bacillus sp. MIR-32 after PAGE and SDS-PAGE. Xylanase activities are associated with at least two major proteins of 18.4 and 19.6 kDa.     

Algicidal effects of yellow clay and the thiazolidinedione derivative TD49 on the fish-killing dinoflagellate Cochlodinium polykrikoides in microcosm experiments

In order to evaluate the potential to control the fish-killing dinoflagellate Cochlodinium polykrikoides, we compared the algicidal effects of the thiazolidinedione derivative TD49 with those of yellow clay in 10-L microcosms. The responses of higher trophic level marine organisms and microbial loop communities to the algicide were also evaluated. In the yellow clay treatments, the concentration of C. polykrikoides was slightly reduced at day 1 of the experiment but remained higher than that of the control, suggesting that the reduction ratio of C. polykrikoides was <20 %. In the 0.8-μM TD49 treatment, the abundance of C. polykrikoides declined by 98 % 1 day following the addition of the algicide. The algicide did not affect nontarget algae including Chaetoceros spp., Skeletonema spp., Cylindrotheca spp., and other species. In all microcosms, bacterial abundance increased abruptly after day 1, then declined over the next 2 days as a result of predation by heterotrophic nanoflagellates and the small protozoan Uronema sp. Predation by the large protozoan species Euplotes sp. on Uronema sp. gradually increased with increasing incubation time in the TD49 treatment. Zooplankton were particularly affected by the environmental changes that occurred in the microcosms following collapse of the C. polykrikoides populations. Striped beak perch were not affected by the yellow clay treatments and concentrations of TD49?C. polykrikoides, whereas the algicide TD49 is effective in controlling the harmful alga. The results imply that the algicide has positive effects on natural microbial communities and is not toxic to nonharmful algae and higher trophic level marine organisms.