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991.
Po-Chun Chang Chun-Jen Wang Chung-Kai You Mou-Chieh Kao 《Biochemical and biophysical research communications》2011,(3):1641
Lipopolysaccharide (LPS) is considered as an important virulence factor of Helicobacter pylori, and contributes to infection persistence and disease severity. ADP-l-glycero-d-manno-heptose-6-epimerase is an enzyme essential for LPS synthesis and understanding of its biochemistry is critical for drug development. We cloned one putative ortholog of Escherichia colirfaD, HP0859, from H. pylori 26695. Determination of the native molecular weight of the recombinant HP0859 protein suggests that the protein is likely a hexamer. NADP+, instead of NAD+, was proved to be the physiological cofactor for HP0859 protein. Circular dichroism spectrum analysis demonstrated that the secondary structure of this protein is significantly altered when the cofactor is removed. We also constructed an HP0859 knockout mutant and examined its phenotypic properties. The HP0859 knockout mutant exhibited a severe truncation of LPS, a decreased growth rate, and a higher susceptibility to novobiocin. Disruption of HP0859 also reduced the adhesive capacity of H. pylori to AGS cells, and the infected cells failed to display the classic hummingbird phenotype. Complementation of the HP0859 knockout mutation restored these phenotypes completely. In conclusion, we demonstrate that HP0859 codes for a protein essential for the LPS inner core biosynthesis in H. pylori and an intact LPS structure contributes to the adherence ability of this bacterium. 相似文献
992.
993.
Livia Garzia Noriyuki Kijima A. Sorana Morrissy Pasqualino De Antonellis Ana Guerreiro-Stucklin Borja L. Holgado Xiaochong Wu Xin Wang Michael Parsons Kory Zayne Alex Manno Claudia Kuzan-Fischer Carolina Nor Laura K. Donovan Jessica Liu Lei Qin Alexandra Garancher Kun-Wei Liu Michael D. Taylor 《Cell》2018,172(5):1050-1062.e14
994.
Retrospective and perspective of rice breeding in China 总被引:1,自引:0,他引:1
Breeding is the art and science of selecting and changing crop traits for the benefit of human beings. For several decades, tremendous efforts have been made by Chinese scientists in rice breeding in improving grain yield, nutrition quality, and environmental performance, achieving substantial progress for global food security. Several generations of crop breeding technologies have been developed, for example, selection of better performance in the field among variants (conventional breeding), application of molecular markers for precise selection (molecular marker assisted breeding), and development of molecular design (molecular breeding by rational design). In this review, we briefly summarize the advances in conventional breeding, functional genomics for genes and networks in rice that regulate important agronomic traits, and molecular breeding in China with focuses on high yield, good quality, stress tolerance, and high nutrient-use efficiency. These findings have paved a new avenue for rational design of crops to develop ideal varieties with super performance and productivity. 相似文献
995.
Photodynamic therapy plays an important role in cancer treatment. In this work, methylene blue (MB)-embedded calcium carbonate nanorods (CaCO3-MB NRs) have been synthesized for pH-responsive photodynamic therapy and ultrasound imaging. The morphology of CaCO3-MB NRs can be controlled by modulating the concentration of Na2CO3 aqueous solution. The generation of effective reactive oxygen species (ROS) were confirmed by 1,3-diphenylisobenzofuran (DPBF) probe. Both photodynamic therapy performance and echogenic performance of CaCO3-MB NRs were investigated to confirm the feasibility of CaCO3-MB nanohybrids for ultrasound image-guided photodynamic therapy. 相似文献
996.
997.
Yuanyuan Li Sanjun Shi Yue Ming Linli Wang Chenwen Li Minghe Luo Ziwei Li Bin Li Jianhong Chen 《Journal of nanobiotechnology》2018,16(1):99
Background
Cancer stem cells (CSCs) are highly proliferative and tumorigenic, which contributes to chemotherapy resistance and tumor occurrence. CSCs specific therapy may achieve excellent therapeutic effects, especially to the drug-resistant tumors.Results
In this study, we developed a kind of targeting nanoparticle system based on cationic albumin functionalized with hyaluronic acid (HA) to target the CD44 overexpressed CSCs. All-trans-retinoic acid (ATRA) was encapsulated in the nanoparticles with ultrahigh encapsulation efficiency (EE%) of 93% and loading content of 8.37%. TEM analysis showed the nanoparticles were spherical, uniform-sized and surrounded by a coating layer consists of HA. Four weeks of continuously measurements of size, PDI and EE% revealed the high stability of nanoparticles. Thanks to HA conjugation on the surface, the resultant nanoparticles (HA-eNPs) demonstrated high affinity and specific binding to CD44-enriched B16F10 cells. In vivo imaging revealed that HA-eNPs can targeted accumulate in tumor-bearing lung of mouse. The cytotoxicity tests illustrated that ATRA-laden HA-eNPs possessed better killing ability to B16F10 cells than free drug or normal nanoparticles in the same dose, indicating its good targeting property. Moreover, HA-eNPs/ATRA treatment decreased side population of B16F10 cells significantly in vitro. Finally, tumor growth was significantly inhibited by HA-eNPs/ATRA in lung metastasis tumor mice.Conclusions
These results demonstrate that the HA functionalized albumin nanoparticles is an efficient system for targeted delivery of antitumor drugs to eliminate the CSCs.
998.
以沙冬青(Ammopiptanthus mongolicus(Maxim.ex Kom.)Cheng f.)幼苗的子叶为材料,对其原生质体的分离、纯化和瞬时表达体系进行了研究。结果表明,子叶原生质体分离的最佳酶解液组成为CPW溶液+3.0%纤维素酶R-10+0.5%离析酶R-10+0.3%半纤维素酶+9.0%甘露醇(p H5.8);最佳酶解条件为室温、避光、40 r/min轻摇14 h。采用W5溶液作为漂洗液将酶解物稀释后进行过滤,将过滤液在4℃、700 r/min条件下离心5 min,所得纯化原生质体的产量约为2.50×106cells/g,活力达到90%;以纯化的原生质体作为受体,利用聚乙二醇(PEG)介导法成功将植物瞬时表达载体p BI-GFP导入其中,转化效率达到50.8%。利用本研究建立的原生质体瞬时表达体系,检测到沙冬青脱水应答转录因子Am DREB1定位于细胞核内。 相似文献
999.
1000.