A comprehensive synthesis unveils the mysteries of phosphate-solubilizing microbes.

Phosphate-solubilizing microbes (PSMs) drive the biogeochemical cycling of phosphorus (P) and hold promise for sustainable agriculture. However, their global distribution, overall diversity and application potential remain unknown. Here, we present the first synthesis of their biogeography, diversity and utility, employing data from 399 papers published between 1981 and 2017, the results of a nationwide field survey in China consisting of 367 soil samples, and a genetic analysis of 12986 genome-sequenced prokaryotic strains. We show that at continental to global scales, the population density of PSMs in environmental samples is correlated with total P rather than pH. Remarkably, positive relationships exist between the population density of soil PSMs and available P, nitrate-nitrogen and dissolved organic carbon in soil, reflecting functional couplings between PSMs and microbes driving biogeochemical cycles of nitrogen and carbon. More than 2704 strains affiliated with at least nine archaeal, 88 fungal and 336 bacterial species were reported as PSMs. Only 2.59% of these strains have been tested for their efficiencies in improving crop growth or yield under field conditions, providing evidence that PSMs are more likely to exert positive effects on wheat growing in alkaline P-deficient soils. Our systematic genetic analysis reveals five promising PSM genera deserving much more attention.

In situ tuning proangiogenic factor-mediated immunotolerance synergizes the tumoricidal immunity via a hypoxia-triggerable liposomal bio-nanoreactor.

Rationale: Vascular abnormality stemming from the hypoxia-driven elevation of proangiogenic factors is a hallmark for many solid malignant tumors, including colorectal cancer (CRC) and its liver metastasis. We report a hypoxia-triggered liposome-supported metal-polyphenol-gene bio-nanoreactor to tune the proangiogenic factor-mediated immunotolerance and synergize the elicited tumoricidal immunity for CRC treatment. Methods: With the aid of polyphenol gallic acid, Cu2+ ion-based intracellular bio-nanoreactor was synthesized for the delivery of small interfering RNA targeting vascular endothelial growth factor and then cloaked with a hybrid liposomal membrane that harbored a hypoxia-responsive azobenzene derivative. In hypoxic tumor, the liposomal shell disintegrated, and a shrunk-size bio-nanoreactor was burst released. Intracellularly, Cu2+ from the bio-nanoreactor catalyzed a Fenton-like reaction with glutathione, which efficiently converted H2O2 to •OH and enabled a chemodynamic therapy (CDT) in tumor sites. With the alleviation of proangiogenic factor-mediated immunotolerance and high production of CDT-induced tumor-associated antigens, robust tumoricidal immunity was co-stimulated. Results: With colorectal tumor and its liver metastasis models, we determined the underlying mechanism of proangiogenic factor-mediated immunotolerance and highlighted that the liposomal bio-nanoreactor could create positive feedback among the critical players in the vascular endothelium and synergize the elicited tumoricidal immunity. Conclusion: Our work provides an alternative strategy for exerting efficient tumoricidal immunity in the proangiogenic factor-upregulated subpopulation of CRC patients and may have a wide-ranging impact on cancer immune-anti-angiogenic complementary therapy in clinics.

Novel phosphate-solubilizing bacteria enhance soil phosphorus cycling following ecological restoration of land degraded by mining.

Little is known about the changes in soil microbial phosphorus (P) cycling potential during terrestrial ecosystem management and restoration, although much research aims to enhance soil P cycling. Here, we used metagenomic sequencing to analyse 18 soil microbial communities at a P-deficient degraded mine site in southern China where ecological restoration was implemented using two soil ameliorants and eight plant species. Our results show that the relative abundances of key genes governing soil microbial P-cycling potential were higher at the restored site than at the unrestored site, indicating enhancement of soil P cycling following restoration. The gcd gene, encoding an enzyme that mediates inorganic P solubilization, was predominant across soil samples and was a major determinant of bioavailable soil P. We reconstructed 39 near-complete bacterial genomes harboring gcd, which represented diverse novel phosphate-solubilizing microbial taxa. Strong correlations were found between the relative abundance of these genomes and bioavailable soil P, suggesting their contributions to the enhancement of soil P cycling. Moreover, 84 mobile genetic elements were detected in the scaffolds containing gcd in the 39 genomes, providing evidence for the role of phage-related horizontal gene transfer in assisting soil microbes to acquire new metabolic potential related to P cycling.

Effect of magnetic nanoparticles size on rheumatoid arthritis targeting and photothermal therapy.

Nanoparticles based multifunctional system exhibits great potential in diagnosis and therapy of rheumatoid arthritis (RA). The size of nanoparticles plays an essential role in biodistribution and cellular uptake, in turn affects the drug delivery efficiency and therapeutic effect. To investigate the optimal size for RA targeting, Fe3O4 nanoparticles with well-defined particle sizes (70-350 nm) and identical surface properties were developed as model nanoparticles. The synthesized Fe3O4 nanoparticles exhibited excellent biocompatibility and showed higher temperature response under irradiation of near infrared light. Size-dependent internalization was observed when incubated with inflammatory cells. Compared with large ones, small nanoparticles were more readily be phagocytized, leading to higher cytotoxicity in vitro. However, the in vivo experiment in CIA mice demonstrated a quite different result that nanoparticles with size of 220 nm exerted better accessibility to inflamed joint and resulted in higher temperature and better therapeutic effect under laser irradiation. This study not only offered a novel method for RA therapy but also a guideline for RA targeted drug carrier design.