Background Focused ultrasound (FUS) combined with microbubbles (MBs) has emerged as a potential approach for opening the blood–brain barrier (BBB) for delivering drugs into the brain. However, MBs range in size of microns and thus can hardly extravasate into the brain parenchyma. Recently, growing attention has been paid to gas vesicles (GVs), which are genetically encoded gas-filled nanostructures with protein shells, due to their potential for extravascular targeting in ultrasound imaging and therapy. However, the use of GVs as agents for BBB opening has not yet been investigated. Methods In this study, GVs were extracted and purified from Halobacterium NRC-1 . Ultrasound imaging performance of GVs was assessed in vitro and in vivo. Then, FUS/GVs-mediated BBB opening for small molecular Evans blue or large molecular liposome delivery across the BBB was examined. Results The results showed a good contrast performance of GVs for brain perfusion ultrasound imaging in vivo. At the acoustic negative pressure of 1.5 MPa, FUS/GVs opened the BBB safely, and effectively enhanced Evans blue and 200-nm liposome delivery into the brain parenchyma. Conclusion Our study suggests that biosynthetic GVs hold great potential to serve as local BBB-opening agents in the development of new targeted drug delivery strategies for central nervous system disorders.
The specific effects of minerals and bacteria in salt on fermented vegetables are unclear. In this study, four different salts were used for radish fermentation to investigate the key factor in salt affecting fermented radish and establish a correlation between the key factor and fermented radish flora. Radish salted with sea salt and well salt had better quality in both industry and laboratory, as reflected by its acidity, color, texture, and flavors. The minerals and halophilic bacteria present in salt can affect the quality of fermented radishes by altering the bacterial community. However, the correlation between minerals and halophilic bacteria remains unclear. The key factor associated to radish fermentation was the dominant halophilic microbes. Bacteria in mineral-rich salts affected radish more on day 35; Salinibacter, Desulfovermiculus, Aliifodinibius, and Halovibrio in salt affected Lactobacillus, Leuconostoc, and Vibrio in radish. In contrast, bacteria in refined salts affected radish more on day 14; Desulfovermiculus, Aliifodinibius, Halovibrio, and Tepidimonas in salt affected most bacteria in radish, particularly lactic acid bacteria (LAB). Key halophilic microbes was found to have a greater effect on fermented radish quality than salt composition. This study provides a theoretical basis for improving the quality and standardization of fermented radish.
危险品化学品经营许可证（带存储）