Marine-derived Bacillus strains have been proved to be a very promising source for natural product leads.However,transformation of environmental strains is much more difficult than that of domesticated strains.Here,we...Marine-derived Bacillus strains have been proved to be a very promising source for natural product leads.However,transformation of environmental strains is much more difficult than that of domesticated strains.Here,we report the development of an efficient and robust electroporation-based transformation system for marine-derived Bacillus marinus B-9987,which is a macrolactin antibiotics producer and a very promising biological control agent against fungal plant diseases.The transformation efficiency was greatly enhanced 103-fold by using unmethylated plasmid to bypass modification-restriction barrier,and using glycine betaine to protect cells from electrical damages during electroporation.Addition of HEPES and 2 mmol L?1MgCl2 further improved the efficiency by additional 2-fold,with a maximum value of 7.1×104 cfu/μg pHT3101.To demonstrate the feasibility and efficiency of the protocol,a green fluorescent protein reporter system was constructed;furthermore,phosphopantetheinyl transferase gene sfp,which is essential to the biosynthesis of polyketides and nonribosomal peptides,was overexpressed in B-9987,leading to increased production of macrolactin A by about 1.6-fold.In addition,this protocol is also applicable to marine-derived Bacillus licheniforms EI-34-6,indicating it could be a reference for other undomesticated Bacillus strains.To our knowledge,this is the first report regarding the transformation of marine-derived Bacillus strain.展开更多
We report that atomically thin two-dimensional silicon quantum sheets(2D Si QSs),prepared by a scalable approach coupling chemical delithiation and cryo-assisted exfoliation,can serve as a highperformance brain photon...We report that atomically thin two-dimensional silicon quantum sheets(2D Si QSs),prepared by a scalable approach coupling chemical delithiation and cryo-assisted exfoliation,can serve as a highperformance brain photonic nanoagent for orthotopic glioma theranostics.With the lateral size of approximately 14.0 nm and thickness of about 1.6 nm,tiny Si QSs possess high mass extinction coefficient of 27.5 Lg^(-1)cm^(-1)and photothermal conversion efficiency of 47.2%at 808 nm,respectively,concurrently contributing to the best photothermal performance among the reported 2 D mono-elemental materials(Xenes).More importantly,Si QSs with low toxicity maintain the trade-off between stability and degradability,paving the way for practical clinical translation in consideration of both storage and action of nanoagents.In vitro Transwell filter experiment reveals that Si QSs could effectively go across the b End.3 cells monolayer.Upon the intravenous injection of Si QSs,orthotopic brain tumors are effectively inhibited under the precise guidance of photoacoustic imaging,and the survival lifetime of brain tumor-bearing mice is increased by two fold.Atomically thin Si QSs with strong light-harvesting capability are expected to provide an effective and robust 2D photonic nanoplatform for the management of brain diseases.展开更多
基金supported by grants from the National Natural Science Foundation of China (31070072,31171201)the Program for New Century Excellent Talents in University (NCET-0900717)partially supported by the National Key Technologies Research and Development Program (2011BAE06B04)
文摘Marine-derived Bacillus strains have been proved to be a very promising source for natural product leads.However,transformation of environmental strains is much more difficult than that of domesticated strains.Here,we report the development of an efficient and robust electroporation-based transformation system for marine-derived Bacillus marinus B-9987,which is a macrolactin antibiotics producer and a very promising biological control agent against fungal plant diseases.The transformation efficiency was greatly enhanced 103-fold by using unmethylated plasmid to bypass modification-restriction barrier,and using glycine betaine to protect cells from electrical damages during electroporation.Addition of HEPES and 2 mmol L?1MgCl2 further improved the efficiency by additional 2-fold,with a maximum value of 7.1×104 cfu/μg pHT3101.To demonstrate the feasibility and efficiency of the protocol,a green fluorescent protein reporter system was constructed;furthermore,phosphopantetheinyl transferase gene sfp,which is essential to the biosynthesis of polyketides and nonribosomal peptides,was overexpressed in B-9987,leading to increased production of macrolactin A by about 1.6-fold.In addition,this protocol is also applicable to marine-derived Bacillus licheniforms EI-34-6,indicating it could be a reference for other undomesticated Bacillus strains.To our knowledge,this is the first report regarding the transformation of marine-derived Bacillus strain.
基金supported by the National Key Research and Development Program of China:Scientific and Technological Innovation Cooperation of Mainland and Macao(2017YFE0120000)the National Natural Science Foundation of China(31800834,81527901,81571745,91859117,81771906,81827807,81901812,and 52071120)+6 种基金the Open Foundation of Shenzhen Bay Laboratory(SZBL2019062801005)the Fundamental Research Funds for the Central Universities(JZ2020HGTB0031 and JZ2018HGPA0273)the Science and Technology Key Project of Shenzhen(JCYJ20160229200902680)the Shenzhen Key Laboratory of Ultrasound Imaging and Therapy(ZDSYS201802061806314)the Shenzhen Double Chain Grant([2018]256)the Natural Science Foundation of Guangdong Province(2014A030312006)the China Postdoctoral Science Foundation(2019 M653129)。
文摘We report that atomically thin two-dimensional silicon quantum sheets(2D Si QSs),prepared by a scalable approach coupling chemical delithiation and cryo-assisted exfoliation,can serve as a highperformance brain photonic nanoagent for orthotopic glioma theranostics.With the lateral size of approximately 14.0 nm and thickness of about 1.6 nm,tiny Si QSs possess high mass extinction coefficient of 27.5 Lg^(-1)cm^(-1)and photothermal conversion efficiency of 47.2%at 808 nm,respectively,concurrently contributing to the best photothermal performance among the reported 2 D mono-elemental materials(Xenes).More importantly,Si QSs with low toxicity maintain the trade-off between stability and degradability,paving the way for practical clinical translation in consideration of both storage and action of nanoagents.In vitro Transwell filter experiment reveals that Si QSs could effectively go across the b End.3 cells monolayer.Upon the intravenous injection of Si QSs,orthotopic brain tumors are effectively inhibited under the precise guidance of photoacoustic imaging,and the survival lifetime of brain tumor-bearing mice is increased by two fold.Atomically thin Si QSs with strong light-harvesting capability are expected to provide an effective and robust 2D photonic nanoplatform for the management of brain diseases.
