Natural exosome-like nanovesicles from edible tea flowers suppress metastatic breast cancer via ROS generation and microbiota modulation

Although several artificial nanotherapeutics have been approved for practical treatment of metastatic breast cancer, their inefficient therapeutic outcomes, serious adverse effects, and high cost of mass production remain crucial challenges. Herein, we developed an alternative strategy to specifically trigger apoptosis of breast tumors and inhibit their lung metastasis by using natural nanovehicles from tea flowers (TFENs). These nanovehicles had desirable particle sizes (131 nm), exosome-like morphology, and negative zeta potentials. Furthermore, TFENs were found to contain large amounts of polyphenols, flavonoids, functional proteins, and lipids. Cell experiments revealed that TFENs showed strong cytotoxicities against cancer cells due to the stimulation of reactive oxygen species (ROS) amplification. The increased intracellular ROS amounts could not only trigger mitochondrial damage, but also arrest cell cycle, resulting in the in vitro anti-proliferation, anti-migration, and anti-invasion activities against breast cancer cells. Further mice investigations demonstrated that TFENs after intravenous (i.v.) injection or oral administration could accumulate in breast tumors and lung metastatic sites, inhibit the growth and metastasis of breast cancer, and modulate gut microbiota. This study brings new insights to the green production of natural exosome-like nanoplatform for the inhibition of breast cancer and its lung metastasis via i.v. and oral routes.

How silicon fertilizer improves nitrogen and phosphorus nutrient availability in paddy soil? / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

In order to reveal the mechanism of silicon (Si) fertilizer in improving nitrogen (N) and phosphorus (P) nutrient availability in paddy soil, we designed a series of soil culture experiments by combining application of varying Si fertilizer concentrations with fixed N and P fertilizer concentrations. Following the recommendations of fertilizer manufacturers and local farmers, we applied Si in concentrations of 0, 5.2, 10.4, 15.6, and 20.8 μg/kg. At each concentration of added Si, the availability of soil N and P nutrients, soil microbial activity, numbers of ammonia-oxidizing bacteria and P-decomposing bacteria which means that the organic P is decomposed into inorganic nutrients which can be absorbed and utilized by plants, and urease and phosphatase activity first increased, and then decreased, as Si was added to the soil. These indicators reached their highest levels with a Si application rate of 15.6 μg/kg, showing values respectively 19.78%, 105.09%, 8.34%, 73.12%, 130.36%, 28.12%, and 20.15% higher than those of the controls. Appropriate Si application (10.4 to 15.6 µg/kg) could significantly increase the richness of the soil microbial community involved in cycling of N and P nutrients in the soil. When the Si application rate was 15.6 μg/kg, parameters for characterizing microbial abundance such as sequence numbers, operational taxonomic unit (OTU) number, and correlation indices of microbial community richness such as Chao1 index, the adaptive coherence estimator (ACE) index, Shannon index, and Simpson index all reached maximum values, with amounts increased by 14.46%, 10.01%, 23.80%, 30.54%, 0.18%, and 2.64%, respectively, compared with the control group. There is also a good correlation between N and P mineralization and addition of Si fertilizer. The correlation coefficients between the ratio of available P/total P (AP/TP) and the number of ammonia-oxidizing bacteria, AP/TP and acid phosphatase activity (AcPA), AP/TP and the Shannon index, the ratio of available N/total amount of N (AN/TN) and the number of ammoniated bacteria, and AN/TN and AcPA were 0.9290, 0.9508, 0.9202, 0.9140, and 0.9366, respectively. In summary, these results revealed that enhancement of soil microbial community structure diversity and soil microbial activity by appropriate application of Si is the key ecological mechanism by which application of Si fertilizer improves N and P nutrient availability.

Influence of users' cognition on information retrieval behaviors in ubiquitous knowledge environment / 中华医学图书情报杂志

Users' cognition and information retrieval are faced with great challenges in ubiquitous knowledge environ-ment. The influence of cognitive factors such as personality traits, cognitive style and ability, knowledge structure and ascribed methods on users' information retrieval behaviors was thus analyzed. It was pointed out that different cognitive factors could influence the retrieval, judgment and absorption of its results,users' satisfaction and continuous use in ubiquitous knowledge environment,with suggestions put forward from the aspects of information retrieval education, information service and information users for improving the users ' knowledge system in knowledge assimilating process by working out effective retrieval strategies using the advantages of cognition.