Phosphoproteomic Analysis Reveals the Predominating Cellular Processes and the Involved Key Phosphoproteins Essential for the Proliferation of Toxoplasma gondii.

PURPOSE: To explore the essential roles of phosphorylation in mediating the proliferation of T. gondii in its cell lytic life. METHODS: We profiled the phosphoproteome data of T. gondii residing in HFF cells for 2 h and 6 h, representing the early- and late-stages of proliferation (ESP and LSP) within its first generation of division. RESULTS: We identified 70 phosphoproteins, among which 8 phosphoproteins were quantified with the phosphorylation level significantly regulated. While only two of the eight phosphoproteins, GRA7 and TGGT1_242070, were significantly down-regulated at the transcriptional level in the group of LSP vs. ESP. Moreover, GO terms correlated with host membrane component were significantly enriched in the category of cellular component, suggesting phosphoprotein played important roles in acquiring essential substance from host cell via manipulating host membrane. Further GO analysis in the categories of molecular function and biological process and pathway analysis revealed that the cellular processes of glucose and lipid metabolism were regulated by T. gondii phosphoproteins such as PMCAA1, LIPIN, Pyk1 and ALD. Additionally, several phosphoproteins were enriched at the central nodes in the protein-protein interaction network, which may have essential roles in T. gondii proliferation including GAP45, MLC1, fructose-1,6-bisphosphate aldolase, GRAs and so on. CONCLUSION: This study revealed the main cellular processes and key phosphoproteins crucial for the intracellular proliferation of T. gondii, which would provide clues to explore the roles of phosphorylation in regulating the development of tachyzoites and new insight into the mechanism of T. gondii development in vitro.

Toxoplasma gondii rhoptry protein (TgROP18) enhances the expression of pro-inflammatory factor in LPS/IFN-γ-induced murine BV2 microglia cells via NF-κB signal pathway.

Toxoplasma gondii, an opportunistic pathogenic protozoan, exhibits a strong predilection to infect the brain, causing severe neurological diseases, such as toxoplasmic encephalitis (TE), in immunocompromised patients. Microglia, the resident immune cells in the brain, is reported to play important roles in regulating the neuroinflammation mediated by T. gondii infection. Here we demonstrated that the tachyzoites of T. gondii RH strain could significantly upregulate the expression levels of microglial M1 phenotype markers including IL-1ß, IL-6, TNF-α, iNOS and IL18 in activated murine BV2 microglia cells, which were regulated by T. gondii rhoptry protein 18 (TgROP18). Moreover, we found that TgROP18 could enhance the expression of M1 phenotype markers in activated murine BV2 microglia cells via activating NF-κB signal pathway. Additionally, TgROP18 was suggested to interact with the host p65 in activated murine BV2 microglia cells and induce the phosphorylation of p65 at S536. In summary, the present study demonstrated that TgROP18 could promote the activated microglia to polarize to M1 phenotype and enhanced the expression of pro-inflammatory factors via activating NF-κB signal pathway, which could contribute to elucidating the mechanism underlying the neuroinflammation mediated by activated microglia in the brain with T. gondii infection.

Light and Magnetic Dual-Responsive Pickering Emulsion Micro-Reactors.

Emulsion droplets can serve as ideal compartments for reactions. In fact, in many cases, the chemical reactions are supposed to be triggered at a desired position and time without change of the system environment. Here, we present a type of light and magnetic dual-responsive Pickering emulsion microreactor by coadsorption of light-sensitive titania (TiO2) and super paramagnetic iron oxide (Fe3O4) nanoparticles at the oil-water interface of emulsion droplets. The droplets encapsulating different reactants in advance can be driven close to each other by an external magnetic field, and then the chemical reaction is triggered by UV illumination due to the contact of the isolated reactants as a result of droplet coalescence. An insight into the incorporation of hydrophobic TiO2 and hydrophilic Fe3O4 nanoparticles simultaneously at the emulsion interface is achieved. On the basis of that, an account is given of the coalescence mechanism of the Pickering emulsion microreactors. Our work not only provides a novel Pickering emulsion microreactor platform for triggering chemical reactions in a nonintrusive and well-controlled way but also opens a promising avenue to construct multifunctional Pickering emulsions by assembly of versatile building block nanoparticles at the interface of emulsion droplets.

Polymer-Protein Conjugate Particles with Biocatalytic Activity for Stabilization of Water-in-Water Emulsions.

Water-in-water (w/w) emulsions are attractive microcompartmentalized platforms due to their outstanding biocompatibility. To address the main disadvantage of poor stability that hampers their practical application, here we report a novel type of polymer-protein conjugate emulsifier obtained by Schiff base synthesis to stabilize w/w emulsions. In particular, the proposed mild approach benefits the modification of proteins of suitable size and wettability as particulate emulsifiers retaining their bioactivity. As demonstrated in a model system, the methoxy polyethylene glycol (mPEG)-urease conjugate particles anchor at the w/w interfaces, where they serve as an effective emulsifier-combined-catalyst and catalyze the hydrolysis of urea in water to ammonium carbonate. Our study is unique in that it employs bioactive particles to stabilize w/w emulsions. Considering the characteristics of all-aqueous, compartmental and interfacial biocatalysis of the system, it will open up new possibilities in the life sciences.

Light-Triggered Release from Pickering Emulsions Stabilized by TiO2 Nanoparticles with Tailored Wettability.

In this work, a new strategy for developing light-triggered Pickering emulsions as smart soft vehicles for on-demand release is proposed. Initially, UV-induced tailored wettability allows anchoring of TiO2 nanoparticles at the interface to prepare stable water in oil emulsions. Such emulsions show the efficacy of microencapsulation and controlled release by demulsification due to the hydrophilic conversion of the TiO2 nanoparticles using a noninvasive light irradiation trigger. A molecule of interest is selected as a model cargo to quantitatively evaluate the as-prepared Pickering emulsions for their encapsulation and release behaviors. Moreover, light-responsive emulsion destabilization mechanism is studied as a function of particle concentration, light wavelength, and light intensity, respectively, determined by drop diameter evolution and droplet coalescence kinetics plots. For consideration of application in life sciences, Pickering emulsions sensitive to visible light are also established based on nitrogen doping of TiO2 nanoparticle emulsifiers.

Switchable Pickering Emulsions Stabilized by Awakened TiO2 Nanoparticle Emulsifiers Using UV/Dark Actuation.

In this work, switchable Pickering emulsions that utilize UV/dark manipulation employ a type of smart TiO2 nanoparticle as emulsifiers. The emulsifiers can be awakened when needed via UV-induced degradation of grafted silanes on TiO2 nanoparticles. By tuning the surface wettability of TiO2 nanoparticles in situ via UV/dark actuation, emulsions stabilized by the nanoparticles can be reversibly switched between the water-in-oil (W/O) type and oil-in-water (O/W) type for several cycles. Due to the convertible wettability, the smart nanoparticle emulsifiers can be settled in either the oil phase or the water phase as desired during phase separation, making it convenient for recycling. The present work provides a facile and noninvasive method to freely manipulate the formation, breakage, and switching of the emulsion; this method has promising potential as a powerful technique for use in energy-efficient and environmentally friendly industries.

[Identification and analysis of Corydalis boweri, Meconopsis horridula and their close related species of the same genus by using ITS2 DNA barcode].

The study is aimed to ensure the quality and safety of medicinal plants by using ITS2 DNA barcode technology to identify Corydalis boweri, Meconopsis horridula and their close related species. The DNA of 13 herb samples including C. boweri and M. horridula from Lhasa of Tibet was extracted, ITS PCR were amplified and sequenced. Both assembled and web downloaded 71 ITS2 sequences were removed of 5. 8S and 28S. Multiple sequence alignment was completed and the intraspecific and interspecific genetic distances were calculated by MEGA 5.0, while the neighbor-joining phylogenetic trees were constructed. We also predicted the ITS2 secondary structure of C. boweri, M. horridula and their close related species. The results showed that ITS2 as DNA barcode was able to identify C. boweri, M. horridula as well as well as their close related species effectively. The established based on ITS2 barcode method provides the regular and safe detection technology for identification of C. boweri, M. horridula and their close related species, adulterants and counterfeits, in order to ensure their quality control, safe medication, reasonable development and utilization.