Physiologically Inspired Mucin Coated Escherichia coli Nissle 1917 Enhances Biotherapy by Regulating the Pathological Microenvironment to Improve Intestinal Colonization.

The delivery of probiotics to the microbiota is a promising method to prevent and treat diseases. However, oral probiotics will suffer from gastrointestinal insults, especially the pathological microenvironment of inflammatory diseases such as reactive oxygen species (ROS) and the exhausted mucus layer, which can limit their survival and colonization in the intestinal tract. Inspired by the fact that probiotics colonized and grew in the mucus layer under physiological conditions, we developed a strategy for a super probiotic (EcN@TA-Ca2+@Mucin) coated with tannic acid and mucin via layer-by-layer technology. We demonstrated that mucin endows probiotics with superior resistance to the harsh environment of the gastrointestinal tract and with strong adhesiveness to the intestine through its interaction with mucus, which enhanced colonization and growth of probiotics in the mucus layer without removing the coating. Moreover, EcN@TA-Ca2+@Mucin can distinctly down-regulate inflammation with ROS scavenging and reduce the side effects of bacterial translocation in inflammatory bowel diseases, increasing the abundance and diversity of the gut microflora. We envision that it is a powerful platform to improve the colonization of probiotics by regulating the pathological microenvironment, which is expected to provide an important perspective for applying the intestinal colonization of probiotics to treat a variety of diseases.

Land use classification of open-pit mine based on multi-scale segmentation and random forest model.

The mining industry production is an important pillar industry in China, while its extensive production activities have led to several ecological and environmental problems. Earth observation technology using high-resolution satellite imagery can help us efficiently obtain information on surface elements, surveying and monitoring various land occupation issues arising from open-pit mining production activities. Conventional pixel-based interpretation methods for high-resolution remote sensing images are restricted by "salt and pepper" noise caused by environmental factors, making it difficult to meet increasing requirements for monitoring accuracy. With the Jingxiang phosphorus mining area in Jingmen Hubei Province as the studied area, this paper uses a multi-scale segmentation algorithm to extract large-scale main characteristic information using a layered mask method based on the hierarchical structure of the image object. The remaining characteristic elements were classified and extracted in combination with the random forest model and characteristic factors to obtain land occupation information related mining industry production, which was compared with the results of the Classification and Regression Tree model. 23 characteristic factors in three aspects were selected, including spectral, geometric and texture characteristics. The methods employed in this study achieved 86% and 0.78 respectively in overall extraction accuracy analysis and the Kappa coefficient analysis, compared to 79% and 0.68 using the conventional method.

Tumor cell-activated "Sustainable ROS Generator" with homogeneous intratumoral distribution property for improved anti-tumor therapy.

Photodynamic therapy (PDT) holds a number of advantages for tumor therapy. However, its therapeutic efficiency is limited by non-sustainable reactive oxygen species (ROS) generation and heterogeneous distribution of photosensitizer (PS) in tumor. Herein, a "Sustainable ROS Generator" (SRG) is developed for efficient antitumor therapy. Methods: SRG was prepared by encapsulating small-sized Mn3O4-Ce6 nanoparticles (MC) into dendritic mesoporous silica nanoparticles (DMSNs) and then enveloped with hyaluronic acid (HA). Due to the high concentration of HAase in tumor tissue, the small-sized MC could be released from DMSNs and homogeneously distributed in whole tumor. Then, the released MC would be uptaken by tumor cells and degraded by high levels of intracellular glutathione (GSH), disrupting intracellular redox homeostasis. More importantly, the released Ce6 could efficiently generate singlet oxygen (1O2) under laser irradiation until the tissue oxygen was exhausted, and the manganese ion (Mn2+) generated by degraded MC would then convert the low toxic by-product (H2O2) of PDT to the most harmful ROS (·OH) for sustainable and recyclable ROS generation. Results: MC could be homogeneously distributed in whole tumor and significantly reduced the level of intracellular GSH. At 2 h after PDT, obvious intracellular ROS production was still observed. Moreover, during oxygen recovery in tumor tissue, ·OH could be continuously produced, and the nanosystem could induce 82% of cell death comparing with 30% of cell death induced by free Ce6. For in vivo PDT, SRG achieved a complete inhibition on tumor growth. Conclusion: Based on these findings, we conclude that the designed SRG could induce sustainable ROS generation, homogeneous intratumoral distribution and intracellular redox homeostasis disruption, presenting an efficient strategy for enhanced ROS-mediated anti-tumor therapy.

Physiological and morphological response of Aphanizomenon flos-aquae to watermelon (Citrullus lanatus) peel aqueous extract.

Natural algaecides are more likely to be specific and biodegradable, and may offer an environmentally friendly method for control of cyanobacterial blooms. We explored, for the first time, the potential for watermelon peel aqueous extract (WMPAE) to control the growth of the harmful blue-green alga Aphanizomenon flos-aquae. The growth inhibition and several physiological parameters of A. flos-aquae, in response to WMPAE, were analyzed. Results showed that WMPAE significantly inhibited the growth of A. flos-aquae in a concentration-dependent way. The highest inhibition reached 94 % after 3 days' treatment with 6 g L-1 of WMPAE and a significant effect was obtained with lower doses and shorter times as well. The cell viability decreased quickly, cell shape changed, and intracellular structural damage occurred. At the same time, the antioxidant enzymes (superoxide dismutase SOD, catalase CAT and peroxidase POD) and malondialdehyde (MDA) levels all increased significantly, indicating that WMPAE between 2-6 g L-1 induced severe oxidative stress and damage to A. flos-aquae. Moreover, production of the four pigments chlorophyll a (Chl a), carotenoids, phycocyanin (PC), and allophycocyanin (APC) were all stimulated, though photosynthesis of A. flos-aquae was clearly inhibited. The maximum quantum yield of photosystem II (Fv/Fm) and the effective quantum yield of photosystem II ( Fv'/Fm') declined sharply, suggesting the decreased photosystem capacity of A. flos-aquae to convert light energy into chemical energy. In addition, non-photochemical quenching (NPQ) of A. flos-aquae increased after a very short time exposure to WMPAE, and decreased significantly with prolonged exposure time, which indicated the failure of photo protection mechanisms. These results suggest that the loss of cell viability, and increases in oxidative stress, and damage to intracellular structure and photosynthetic systems might be the mechanisms for the inhibitory effects. Our results suggested that WMPAE could be a novel and effective approach for controlling the growth of A. flos-aquae in aquatic environments.

Phosphorus release from cyanobacterial blooms during their decline period in eutrophic Dianchi Lake, China.

The phosphorus (P) release from bloom-cyanobacterium during its decline period is one of the most important parts involved in lake P-biogeochemical cycle, which is an important nutrient self-regulating process to sustain eutrophic status in lakes. An in situ experiment was set up to study the phosphorus release mechanisms of cyanobacterial blooms in Dianchi Lake during its decline period. In the enclosure, the cyanobacteria were dying out gradually and this process further affected the water quality parameters and lead to P release from bloom-cyanobacteria. The pH and electric conductivity (EC) increased substantially, while the redox potential (ORP) decreased during the whole experimental period. Among all the released P forms, the orthophosphate (ortho-P) was the main released P form and accounted for 96.7 and 67.8% of the total phosphorus (TP) increment in the water and the TP reduction in algae respectively. According to the TP in sediment and lost P of overlying water column, it could be concluded that the ortho-P released from algae was absorbed by sediment as well. The release of TP, organic P (OP), and ortho-P from bloom-cyanobacteria all followed the first-order kinetics, and the release rate of ortho-P was much higher than that of OP (p < 0.05). Furthermore, according to the total extracellular polysaccharide (EPS) determination and related Pearson's correlation analysis, the release of TP and ortho-P from bloom-cyanobacteria would probably depend on the reduction of capsular polysaccharide (CPS) and colonial sheath disaggregation. In conclusion, a large amount of ortho-P was released and adsorbed by sediment gradually during cyanobacterial bloom decline period, and these bioavailable P could provide the sufficient nutrient for newborn cyanobacteria and could contribute to the construction of a new internal P cycle among sediment, water, and cyanobacterial bloom.