In this work, a matrix metalloproteinase (MMP)-triggered tumor targeted mesoporous silica nanoparticle (MSN) is designed to realize near-infrared (NIR) photothermal-responsive drug release and combined chemo/photothermal tumor therapy. Indocyanine green (ICG) and doxorubicin (DOX) are both loaded in the MSN modified with thermal-cleavable gatekeeper (Azo-CD), which can be decapped by ICG-generated hyperthermia under NIR illumination. A peptidic sequence containing a short PEG chain, matrix metalloproteinase (MMP) substrate (PLGVR) and tumor cell targeting motif (RGD) are further decorated on the MSN via a host-guest interaction. The PEG chain can protect the MSN during the circulation and be cleaved off in the tumor tissues with overexpressed MMP, and then the RGD motif is switched on to target tumor cells. After the tumor-triggered targeting process, the NIR irradiation guided by ICG fluorescence can trigger cytosol drug release and realize combined chemo/photothermal therapy.

No abstract

Wheat (Triticum aestivum L.) is an important cereal crop, widely grown throughout the temperate zones, and also suitable for cultivation at higher elevations. Fusarium head blight (FHB) is a highly destructive disease of wheat throughout the globe. In July 2020, serious wheat FHB symptoms were observed in open fields located in Linzhi City, southeast of Tibet, China. The causal agent was identified as Fusarium avenaceum (Fr.) Sacc. by amplification and sequencing of the internal transcribed spacer (ITS) region, translation elongation factor 1-alpha (EF-1α) gene, and RNA polymerase II subunit (RPB-2) gene, as well as by morphological characterization. Koch’s postulates were confirmed by a pathogenicity test on healthy spikes, including re-isolation and identification. To our knowledge, this is the first report of F. avenaceum causing FHB on wheat in Tibet, China. Moreover, to determine pathogen characteristics that may be useful for future disease management, the utilization of different carbon and nitrogen resources, temperature, light, and ultraviolet (UV) irradiation on mycelium growth and conidia germination were studied. Soluble starch and peptone were the best carbon, and nitrogen source for the pathogen respectively. The optimal temperatures for the pathogen’s mycelium growth and conidia germination were 15–20°C, matching the average temperature during the growing season in Linzhi (Tibet). Meanwhile, alternating 8-h light and 16-h dark was shown to be conducive to mycelia growth, and complete darkness facilitated conidia germination. In addition, UV Irradiation of 48 MJ/cm2, approximately 100 times of the local condition, did not inhibit the germination of conidia. Furthermore, in vitro screening of effective fungicides was conducted. Among the seven tested pesticides, carbendazim showed the best inhibition rate, with an EC50 (concentration for 50% of maximal effect) value of 2.1 mg/L. Propiconazole also showed sufficient inhibitory effects against F. avenaceum, with an EC50 value of 2.6 mg/L. The study provides insights into the newly identified causal agent of wheat FHB in Tibet, China, as well as first pathogen characteristics and promising candidate substances for its management.

Because of swainonine-producing endophytic fungal, Oxytropis glacialis is one of the main poisonous weeds in the alpine grassland and desert grassland of the Qinghai-Tibet Plateau (QTP). It has a severe impact on grassland degradation on the QTP. In this manuscript, the Internally Transcribed Spacer (ITS) region of fungal communities in the soil of the O. glacialis root system was sequenced by high-throughput sequencing and analyzed by bioinformatics methods. The physical and chemical properties of the soil samples were analyzed in combination with the fungal diversity and its relationship with the soil physical and chemical factors. The results showed that the soil fungal community in the O. glacialis root system are rich in diversity in different ecological environments and are most affected by the soil pH value and organic matter. The swainonine-producing fungal Embellisia oxytropis was first detected in the soil of the O. glacialis root system. This finding provides data to support the next step in demonstrating the horizontal spread of swainone-producing fungal from O. glacialis to soil. In addition, a stable network of core flora has a facilitating effect on the formation of O. glacialis as a dominant species in alpine ecosystems.