The synthesis of a new type of X-ray-sensitive compound ＂di-（1-hydroxylundecyl） diselenide＂ and its application in the preparation of a new type of liposome with X-ray sensitivity was reported.This new liposome wa...The synthesis of a new type of X-ray-sensitive compound ＂di-（1-hydroxylundecyl） diselenide＂ and its application in the preparation of a new type of liposome with X-ray sensitivity was reported.This new liposome was synthesized to encapsulate doxorubicin hydrochloride（Dox）,with its physical and chemical properties,stability,and radiation sensitivity determined.Based on the pH-gradient method,liposomal Dox was prepared via ultrasonic emulsification and then purified on a Sephadex G50 mini-column.UV spectrophotometry and liquid chromatography were used to detect the encapsulation efficiency and radiation sensitivity of the Dox-loaded liposome.The results show that through changes in release rate,this liposome shows a relative radiosensitivity.In terms of radiation sensitivity,the drug leak rate of the X-ray-sensitive Dox-loaded liposome increased gradually and peaked at 65.4% under the X-ray radiation of a dose of 10 Gy or more than 10 Gy,which is significantly different from that of ordinary liposomes.Meanwhile,X-ray-sensitive Dox-loaded liposome has a good dispersion stability,with an average particle size of approximate 120 nm.The efficiency of this liposome encapsulating Dox was 75.84%,slightly lower than that of ordinary liposomes.The X-ray-sensitive Dox-loaded liposome exhibited suspension stability within 30 d of storage at 4 °C,without visible precipitation.Di-（1-hydroxylundecyl） diselenide is safe and noncytotoxic and compared with those of synthetic phospholipids its synthesis is low cost and does not require complex conditions.展开更多
Bacterial diversity of 14 sites of the East China Sea was investigated by culture-dependent methods. The impact of human activities on marine bacteria was primarily studied and characteristics of bacteria communities ...Bacterial diversity of 14 sites of the East China Sea was investigated by culture-dependent methods. The impact of human activities on marine bacteria was primarily studied and characteristics of bacteria communities in different areas were analyzed. A total of 396 strains were obtained. These strains belong to 4 phyla, 9 classes and 146 species according to 16S rDNA sequences alignment. For 32 strains, the 16S rDNA sequences similarities between isolated strains and their most closely related species were lower than 98%. The result indicated that there are abundant microbial diversity and a large number of unknown microbial resources in the East China Sea. Isolated strains were dominated byy-proteobacteria （64%）, ct-proteobacteria （18%） and Firmicutes （15%）. Actinobacteria and Bacteroidetes were less than 3%. Microbial community composition, diversity and abundance among areas with varies distances from land were different. The far the regions from the land, the lower the Shannon index （H＇） and the Margalef index （DMg） values were.展开更多
基金Supported by the National Basic Research Program of China(No.2007CB808000)the National Natural Science Foundation of China(Nos.81072337,21074066)
文摘The synthesis of a new type of X-ray-sensitive compound ＂di-（1-hydroxylundecyl） diselenide＂ and its application in the preparation of a new type of liposome with X-ray sensitivity was reported.This new liposome was synthesized to encapsulate doxorubicin hydrochloride（Dox）,with its physical and chemical properties,stability,and radiation sensitivity determined.Based on the pH-gradient method,liposomal Dox was prepared via ultrasonic emulsification and then purified on a Sephadex G50 mini-column.UV spectrophotometry and liquid chromatography were used to detect the encapsulation efficiency and radiation sensitivity of the Dox-loaded liposome.The results show that through changes in release rate,this liposome shows a relative radiosensitivity.In terms of radiation sensitivity,the drug leak rate of the X-ray-sensitive Dox-loaded liposome increased gradually and peaked at 65.4% under the X-ray radiation of a dose of 10 Gy or more than 10 Gy,which is significantly different from that of ordinary liposomes.Meanwhile,X-ray-sensitive Dox-loaded liposome has a good dispersion stability,with an average particle size of approximate 120 nm.The efficiency of this liposome encapsulating Dox was 75.84%,slightly lower than that of ordinary liposomes.The X-ray-sensitive Dox-loaded liposome exhibited suspension stability within 30 d of storage at 4 °C,without visible precipitation.Di-（1-hydroxylundecyl） diselenide is safe and noncytotoxic and compared with those of synthetic phospholipids its synthesis is low cost and does not require complex conditions.
文摘Bacterial diversity of 14 sites of the East China Sea was investigated by culture-dependent methods. The impact of human activities on marine bacteria was primarily studied and characteristics of bacteria communities in different areas were analyzed. A total of 396 strains were obtained. These strains belong to 4 phyla, 9 classes and 146 species according to 16S rDNA sequences alignment. For 32 strains, the 16S rDNA sequences similarities between isolated strains and their most closely related species were lower than 98%. The result indicated that there are abundant microbial diversity and a large number of unknown microbial resources in the East China Sea. Isolated strains were dominated byy-proteobacteria （64%）, ct-proteobacteria （18%） and Firmicutes （15%）. Actinobacteria and Bacteroidetes were less than 3%. Microbial community composition, diversity and abundance among areas with varies distances from land were different. The far the regions from the land, the lower the Shannon index （H＇） and the Margalef index （DMg） values were.
