anoxygenic phototrophic bacteria （AAPB）, which form a unique functional group of heterotrophic bacteria, have the abilit,to utilize light energy. The impact of carbon source and light intensity on the growth and bac...anoxygenic phototrophic bacteria （AAPB）, which form a unique functional group of heterotrophic bacteria, have the abilit,to utilize light energy. The impact of carbon source and light intensity on the growth and bacteriochlorophyn a （ BChl a） expression of a typical strain of AAPB, Erythrobacter longus strain DSMZ6997 was examined during batch culture and continuous culture. The results showed that the expression of BChl a in DSMZ6997 was regulated by both carbon-source and light conditions, and was stimulated by low availability of carbon but inhibited by light to a certain extent at 300 lx and completely at 1 500 lx. In contrast, cell abundance, and even cell size of this strain, was substantially enhanced under light/dark cycle cultivation conditions over dark conditions, indicating the promotion of growth by light. These results led to the conclusion that utilization of light through BChl a helps AAPB to survive under carbon stress, while light at high intensity is harmful to the synthesis of BChl a in AAPB.展开更多
Photodynamic therapy(PDT)utilizes light and photosensitizer(PS)to generate reactive oxygen species(ROS)to kill cancer cells,presenting a promising strategy as an anti-cancer treatment.However,the low hydrophilicity an...Photodynamic therapy(PDT)utilizes light and photosensitizer(PS)to generate reactive oxygen species(ROS)to kill cancer cells,presenting a promising strategy as an anti-cancer treatment.However,the low hydrophilicity and poor targeting of currently used PSs,as well as the abnormal tumor microenvironment(TME),limit the clinical application of PDT.Herein,nontoxic liposomes with the ability to incorporate both hydrophilic and hydrophobic PS are used as the nanocarrier to co-load Hemoporfin,L-buthionine sulfoximine(BSO),and catalase(CAT)to obtain BSO/CAT@Liposomes-Hemoporfin nanoparticles(BCHL NPs),which could be used to remodel the TME and to enhance Hemoporfin-mediated PDT efficacy.BCHL NPs exhibit a long blood circulation time and can accumulate in the tumor.BSO can reduce the cytosolic concentration of glutathione(GSH),a natural scavenger of ROS.CAT catalyzes the endogenously overexpressed H_(2)O_(2)in the tumor site into H_(2)O and O_(2),thus relieving tumor hypoxia and enhancing ROS generation.Upon irradiation,the synergetic effects of reduced GSH synthesis by BSO and relieved hypoxia by CAT were observed in 4T1 tumor-bearing mouse model.Compared to the tumor treated by free Hemoporfin,BCHL NPs-mediated PDT resulted in 1.25-fold higher inhibition of tumor growth due to the enhanced ROS generation.The present study provides insight into the design of efficient strategies for enhanced clinic Hemoporfin-mediated PDT efficiency.展开更多
基金This study was supported by the National Natural Science Foundation of China under contract Nos 40232021,40576063 and 40521003the Ministry of Science and Technology of China under contract Nos 2005AA635240 and 2003DF000040.
文摘anoxygenic phototrophic bacteria （AAPB）, which form a unique functional group of heterotrophic bacteria, have the abilit,to utilize light energy. The impact of carbon source and light intensity on the growth and bacteriochlorophyn a （ BChl a） expression of a typical strain of AAPB, Erythrobacter longus strain DSMZ6997 was examined during batch culture and continuous culture. The results showed that the expression of BChl a in DSMZ6997 was regulated by both carbon-source and light conditions, and was stimulated by low availability of carbon but inhibited by light to a certain extent at 300 lx and completely at 1 500 lx. In contrast, cell abundance, and even cell size of this strain, was substantially enhanced under light/dark cycle cultivation conditions over dark conditions, indicating the promotion of growth by light. These results led to the conclusion that utilization of light through BChl a helps AAPB to survive under carbon stress, while light at high intensity is harmful to the synthesis of BChl a in AAPB.
基金National Natural Science Foundation of China,Grant/Award Numbers:62227823,61935004。
文摘Photodynamic therapy(PDT)utilizes light and photosensitizer(PS)to generate reactive oxygen species(ROS)to kill cancer cells,presenting a promising strategy as an anti-cancer treatment.However,the low hydrophilicity and poor targeting of currently used PSs,as well as the abnormal tumor microenvironment(TME),limit the clinical application of PDT.Herein,nontoxic liposomes with the ability to incorporate both hydrophilic and hydrophobic PS are used as the nanocarrier to co-load Hemoporfin,L-buthionine sulfoximine(BSO),and catalase(CAT)to obtain BSO/CAT@Liposomes-Hemoporfin nanoparticles(BCHL NPs),which could be used to remodel the TME and to enhance Hemoporfin-mediated PDT efficacy.BCHL NPs exhibit a long blood circulation time and can accumulate in the tumor.BSO can reduce the cytosolic concentration of glutathione(GSH),a natural scavenger of ROS.CAT catalyzes the endogenously overexpressed H_(2)O_(2)in the tumor site into H_(2)O and O_(2),thus relieving tumor hypoxia and enhancing ROS generation.Upon irradiation,the synergetic effects of reduced GSH synthesis by BSO and relieved hypoxia by CAT were observed in 4T1 tumor-bearing mouse model.Compared to the tumor treated by free Hemoporfin,BCHL NPs-mediated PDT resulted in 1.25-fold higher inhibition of tumor growth due to the enhanced ROS generation.The present study provides insight into the design of efficient strategies for enhanced clinic Hemoporfin-mediated PDT efficiency.
