Despite the widely observed predominance of Cand . Patescibacteria in subsurface communities, their input source and ecophysiology are poorly understood. Here we study mechanisms of the formation of a groundwater microbiome and the subsequent differentiation of Cand . Patescibacteria. In the Hainich Critical Zone Exploratory, Germany, we trace the input of microorganisms from forested soils of preferential recharge areas through fractured aquifers along a 5.4 km hillslope well transect. Cand . Patescibacteria were preferentially mobilized from soils and constituted 66% of species-level OTUs shared between seepage and shallow groundwater. These OTUs, mostly related to Cand . Kaiserbacteraceae, Cand . Nomurabacteraceae, and unclassified UBA9983 at the family level, represented a relative abundance of 71.4% of the Cand . Patescibacteria community at the shallowest groundwater well, and still 44.4% at the end of the transect. Several Cand . Patescibacteria subclass-level groups exhibited preferences for different conditions in the two aquifer assemblages investigated: Cand . Kaiserbacteraceae surprisingly showed positive correlations with oxygen concentrations, while Cand . Nomurabacteraceae were negatively correlated. Co-occurrence network analysis revealed a central role of Cand . Patescibacteria in the groundwater microbial communities and pointed to potential associations with specific organisms, including abundant autotrophic taxa involved in nitrogen, sulfur and iron cycling. Strong associations among Cand . Patescibacteria themselves further suggested that for many groups within this phylum, distribution was mainly driven by conditions commonly supporting a fermentative life style without direct dependence on specific hosts. We propose that import from soil, and community differentiation driven by hydrochemical conditions, including the availability of organic resources and potential hosts, determine the success of Cand . Patescibacteria in groundwater environments.
Therapeutic strategies based on modulation of microRNAs (miRNAs) activity hold much promise for cancer therapy, but for clinical applications, the effi cient delivery of miRNAs to tumor cells or tumor tissues remains a great challenge. In this work, microRNA-181b inhibitor (anti-miR-181b) is successfully condensed into polyethyleneimine (PEI)-modifi ed and folate receptor (FR)-targeted PEGylated gold nanocages (AuNCs). This delivery system is designated as anti-miR-181b/PTPAuNCs nanocomplexes (PTPAuNC-NPs), which begin with chemical modifi cation of AuNCs with SH-PEG 5000 -folic acid (SH-PEG 5000 -FA) and SH-PEG 5000 through a gold-sulfur bond, followed by conjugating PEI using lipoic acid as a linker. Finally anti-miR-181b is condensed via electrostatic interactions. In vitro and in vivo experiments show that PTPAuNC-NPs can effi ciently deliver anti-miR-181b into target sites to suppress tumor growth, and considerably decrease tumor volumes in SMMC-7721 tumor-bearing nude mice under near-infrared radiation. All these results suggest that PTPAuNC-NP gene delivery system with combination of gene therapy and photothermal therapy will be of great potential use in future cancer therapy.
The impact of conspecific and heterospecific neighboring plants on soil bacterial and fungal communities has never been explored in a forest ecosystem. In the present study, we first investigated soil microbial communities in three plantations: Larix kaempferi monoculture, L. olgensis monoculture and their mixture. Then, a two-year growth experiment was conducted to investigate the effects of intra-and inter-specific plant interactions of L. kaempferi and L. olgensis on rhizosphere microbial communities in different nitrogen conditions. The results demonstrated clear differences in the beta-diversity and composition of bacteria and fungi among the three plantations, which implied different effects of plant-plant interactions on soil microbial communities. The results of the pot experiment showed that L. kaempferi suffered from greater negative effects from its conspecific neighbor regardless of the N fertilization, whereas the negative effect declined when L. kaempferi was grown with L. olgensis under N fertilization. Changes in intra-and inter-specific plant interactions significantly impacted the chemical and biological properties of soil under N fertilization, with lower concentrations of NH4 + , and lower soil microbial biomass (CMic) and soil carbon nitrogen biomass (NMic) under intra-specific plant interactions of L. kaempferi (KK) compared to inter-specific interactions of L. kaempferi and L. olgensis (KO). N fertilization increased bacterial and fungal alpha diversities in the rhizosphere soil of KO. For the beta diversity, the PERMANOVA results demonstrated that there was a significant impact of intra-and inter-specific plant interactions on soil microbial communities, with KK significantly differing from intra-specific plant interactions of L. olgensis (OO) and KO. The two plant species 3 and N fertilization showed specific effects on the soil microbial composition, particularly on the fungal community. Both L. olgensis and N fertilization increased the abundance of Ascomycota but reduced that of Basidiomycota, and even shifted the dominance of Basidiomycota to Ascomycota in KO under N fertilization. Based on our results, we suggest that L. kaempferi planted with L. olgensis under N fertilization may be an efficient way to promote the productivity of plantations.
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