结直肠癌(colorectal cancer,CRC)是中国第二大常见癌症。研究表明,虽然环境和遗传因素在CRC的发病机制中起主要作用,但营养因素(维生素D)依然在CRC的病程发展中发挥重要作用。维生素D及其受体(vitamin D receptor,VDR)通过多种机制参...结直肠癌(colorectal cancer,CRC)是中国第二大常见癌症。研究表明,虽然环境和遗传因素在CRC的发病机制中起主要作用,但营养因素(维生素D)依然在CRC的病程发展中发挥重要作用。维生素D及其受体(vitamin D receptor,VDR)通过多种机制参与人体健康和疾病的发展,其中调节肠道菌群是重要的途径之一。在肠道菌群调节中,肠道菌群变异对肠道和肠外疾病如CRC的前中后期病程具有不同程度的影响。本综述重点阐述了维生素D通过肠道菌群调节对CRC的预防作用,重点剖析了维生素D、肠道微生物稳态和CRC之间的不同关联。此外,本文也简单介绍维生素D对CRC发挥的多种预防作用及其作用机制,包括直接抗肿瘤机制、对免疫系统的影响和肠道菌群调节机制。展开更多
Electrochemical sensing of carcinoembryonic antigen(CEA)on a gold electrode modified by the se- quential incorporation of the mediator,thionine(Thi),and gold nanoparticles(nano-Au),through co- valent linkage and elect...Electrochemical sensing of carcinoembryonic antigen(CEA)on a gold electrode modified by the se- quential incorporation of the mediator,thionine(Thi),and gold nanoparticles(nano-Au),through co- valent linkage and electrostatic interactions onto a self-assembled monolayer configuration is de- scribed in this paper.The enzyme,horseradish peroxidase(HRP),was employed to block the possible remaining active sites of the nano-Au monolayer,avoid the non-specific adsorption,instead of bovine serum albumin(BSA),and amplify the response of the antigen-antibody reaction.Electrochemical ex- periments indicated highly efficient electron transfer by the imbedded Thi mediator and adsorbed nano-Au.The HRP kept its activity after immobilization,and the studied electrode showed sensitive response to CEA and high stability during a long period of storage.The working range for the system was 2.5 to 80.0 ng/mL with a detection limit of 0.90 ng/mL.The model membrane system in this work is a potential biosensor for mimicking the other immunosensor and enzyme sensor.展开更多
Beauvericin, a cyclohexadepsipeptide-possessing natural product with synergistic antifungal, insecticidal, and cytotoxic activities. We isolated and characterized the fpBeas gene cluster, devoted to beauvericin biosyn...Beauvericin, a cyclohexadepsipeptide-possessing natural product with synergistic antifungal, insecticidal, and cytotoxic activities. We isolated and characterized the fpBeas gene cluster, devoted to beauvericin biosynthesis, from the filamentous fungus Fusarium proliferatum LF061. Targeted inactivation of the F. proliferatum genomic copy of fpBeas abolished the production of beauvericin. Comparative sequence analysis of the FpBEAS showed 74% similarity with the BbBEAS that synthesizes the cyclic trimeric ester beauvericin in Beauveria bassiana, which assembles N-methyl-dipeptidol monomer intermediates by the programmed iterative use of the nonribosomal peptide synthetase modules. Differences between the organization of the beauvericin loci in F. proliferaturm and B. bassiana revealed the mechanism for high production of beauvericin in F. proliferatum. Our work provides new insights into beauvericin biosynthesis, and may lead to beauvericin overproduction and creation of new analogs via synthetic biology approaches.展开更多
文摘结直肠癌(colorectal cancer,CRC)是中国第二大常见癌症。研究表明,虽然环境和遗传因素在CRC的发病机制中起主要作用,但营养因素(维生素D)依然在CRC的病程发展中发挥重要作用。维生素D及其受体(vitamin D receptor,VDR)通过多种机制参与人体健康和疾病的发展,其中调节肠道菌群是重要的途径之一。在肠道菌群调节中,肠道菌群变异对肠道和肠外疾病如CRC的前中后期病程具有不同程度的影响。本综述重点阐述了维生素D通过肠道菌群调节对CRC的预防作用,重点剖析了维生素D、肠道微生物稳态和CRC之间的不同关联。此外,本文也简单介绍维生素D对CRC发挥的多种预防作用及其作用机制,包括直接抗肿瘤机制、对免疫系统的影响和肠道菌群调节机制。
基金the National Natural Science Foundation of China(Grant No.20675064)Natural Science Foundation of Chongqing City(Grant Nos.CSTC-2004BB4149 and 2005BB4100)the High Technology Project Foundation ofSouthwest University(XSGX02),China
文摘Electrochemical sensing of carcinoembryonic antigen(CEA)on a gold electrode modified by the se- quential incorporation of the mediator,thionine(Thi),and gold nanoparticles(nano-Au),through co- valent linkage and electrostatic interactions onto a self-assembled monolayer configuration is de- scribed in this paper.The enzyme,horseradish peroxidase(HRP),was employed to block the possible remaining active sites of the nano-Au monolayer,avoid the non-specific adsorption,instead of bovine serum albumin(BSA),and amplify the response of the antigen-antibody reaction.Electrochemical ex- periments indicated highly efficient electron transfer by the imbedded Thi mediator and adsorbed nano-Au.The HRP kept its activity after immobilization,and the studied electrode showed sensitive response to CEA and high stability during a long period of storage.The working range for the system was 2.5 to 80.0 ng/mL with a detection limit of 0.90 ng/mL.The model membrane system in this work is a potential biosensor for mimicking the other immunosensor and enzyme sensor.
基金supported by the National Basic Research Program of China (2013CB734000, 2012CB725200)the CAS Pillar Program (XDA04074000)+1 种基金Ministry of Science and Technology of China (2011ZX11102-011-11)ZHANG LiXin is an Awardee for the National Distinguished Young Scholar Program in China
文摘Beauvericin, a cyclohexadepsipeptide-possessing natural product with synergistic antifungal, insecticidal, and cytotoxic activities. We isolated and characterized the fpBeas gene cluster, devoted to beauvericin biosynthesis, from the filamentous fungus Fusarium proliferatum LF061. Targeted inactivation of the F. proliferatum genomic copy of fpBeas abolished the production of beauvericin. Comparative sequence analysis of the FpBEAS showed 74% similarity with the BbBEAS that synthesizes the cyclic trimeric ester beauvericin in Beauveria bassiana, which assembles N-methyl-dipeptidol monomer intermediates by the programmed iterative use of the nonribosomal peptide synthetase modules. Differences between the organization of the beauvericin loci in F. proliferaturm and B. bassiana revealed the mechanism for high production of beauvericin in F. proliferatum. Our work provides new insights into beauvericin biosynthesis, and may lead to beauvericin overproduction and creation of new analogs via synthetic biology approaches.
