Comparative Phosphoproteomic Analysis of Sporulated Oocysts and Tachyzoites of Toxoplasma gondii Reveals Stage-Specific Patterns

Toxoplasma gondii is an obligate intracellular protozoan of severe threat to humans and livestock, whose life history harbors both gamic and apogamic stages. Chinese 1 (ToxoDB#9) was a preponderant genotype epidemic in food-derived animals and humans in China, with a different pathogenesis from the strains from the other nations of the world. Posttranslational modifications (PTMs) of proteins were critical mediators of the biology, developmental transforms, and pathogenesis of protozoan parasites. The phosphoprotein profiling and the difference between the developmental phases of T. gondii, contributing to development and infectivity, remain unknown. A quantitative phosphoproteomic approach using IBT integrated with TiO₂ affinity chromatography was applied to identify and analyze the difference in the phosphoproteomes between the sporulated oocysts and the tachyzoites of the virulent ToxoDB#9 (PYS) strain of T. gondii. A total of 4058 differential phosphopeptides, consisting of 2597 upregulated and 1461 downregulated phosphopeptides, were characterized between sporulated the oocysts and tachyzoites. Twenty-one motifs extracted from the upregulated phosphopeptides contained 19 serine motifs and 2 threonine motifs (GxxTP and TP), whereas 16 motifs identified from downregulated phosphopeptides included 13 serine motifs and 3 threonine motifs (KxxT, RxxT, and TP). Beyond the traditional kinases, some infrequent classes of kinases, including Ab1, EGFR, INSR, Jak, Src and Syk, were found to be corresponding to motifs from the upregulated and downregulated phosphopeptides. Remarkable functional properties of the differentially expressed phosphoproteins were discovered by GO analysis, KEGG pathway analysis, and STRING analysis. S8GFS8 (DNMT1-RFD domain-containing protein) and S8F5G5 (Histone kinase SNF1) were the two most connected peptides in the kinase-associated network. Out of these, phosphorylated modifications in histone kinase SNF1 have functioned in mitosis and interphase of T. gondii, as well as in the regulation of gene expression relevant to differentiation. Our study discovered a remarkable difference in the abundance of phosphopeptides between the sporulated oocysts and tachyzoites of the virulent ToxoDB#9 (PYS) strain of T. gondii, which may provide a new resource for understanding stage-specific differences in PTMs and may enhance the illustration of the regulatory mechanisms contributing to the development and infectivity of T. gondii.     

Drop-Activation:Implicit Parameter Reduction and Harmonious Regularization

Overfitting frequently occurs in deep learning.In this paper,we propose a novel regu-larization method called drop-activation to reduce overfitting and improve ...     

Controllable soliton transition and interaction in nonlocal nonlinear media

Nonlinear Dynamics - Two kinds of controllable evolutions of optical solitons are predicted in nonlocal nonlinear media by gradually tuning the characteristic length of response function. On the...     

4.8 nm Concave {M_(72)}(M=Co,Ni,Fe) metal-organic polyhedra capped by 18 calixarenes

Three 4.8 nm isostructural{M₇₂}(M=Co^Ⅱ for CIAC-128,Ni^Ⅱ for CIAC-129,Fe^Ⅱ for CIAC-130) metal-organic polyhedra(MOPs) are constructed by eighteen M₄-p-tert-butylthiacalix[4]arene (M₄-TC4A) units bridged via sixteen four-connected 5,5′-(1H-1,2,4-triazole-3,5-diyl) diisophthalic acid (H₄TADIPA) linkers.These MOPs are featured with a rarely reported concave coordination cage,which can be simplified as a squeezed double-decker hexagonal prism pressed from the top and bottom hexagonal faces.Furthermore,CIAC-128,CIAC-129 and CIAC-130 are the highest nuclearity discrete clusters of Co,Ni and Fe reported so far.CIAC-128 has higher separation selectivity of C₃H₈ than CH₄ under ambient conditions,and also exhibits separation selectivity for C₂H₆/CH₄,C₂H₂/CH₄,and C₂H₄/CH₄.In addition,CIAC-128 can provide the cavity for the confined synthesis of noble metal nanoclusters such as Pd nanoclusters and the resulting Pd@CIAC-128 hybrids show higher electrocatalytic activity than commercial Pt/C towards hydrogen evolution reaction (HER).     

DFT insight into asymmetric alkyl–alkyl bond formation via nickel-catalysed enantioconvergent reductive coupling of racemic electrophiles with olefins

A DFT study has been conducted to understand the asymmetric alkyl–alkyl bond formation through nickel-catalysed reductive coupling of racemic alkyl bromide with olefin in the presence of hydrosilane and K₃PO₄. The key findings of the study include: (i) under the reductive experimental conditions, the Ni(ii) precursor is easily activated/reduced to Ni(0) species which can serve as an active species to start a Ni(0)/Ni(ii) catalytic cycle. (ii) Alternatively, the reaction may proceed via a Ni(i)/Ni(ii)/Ni(iii) catalytic cycle starting with a Ni(i) species such as Ni(i)–Br. The generation of a Ni(i) active species via comproportionation of Ni(ii) and Ni(0) species is highly unlikely, because the necessary Ni(0) species is strongly stabilized by olefin. Alternatively, a cage effect enabled generation of a Ni(i) active catalyst from the Ni(ii) species involved in the Ni(0)/Ni(ii) cycle was proposed to be a viable mechanism. (iii) In both catalytic cycles, K₃PO₄ greatly facilitates the hydrosilane hydride transfer for reducing olefin to an alkyl coupling partner. The reduction proceeds by converting a Ni–Br bond to a Ni–H bond via hydrosilane hydride transfer to a Ni–alkyl bond via olefin insertion. On the basis of two catalytic cycles, the origins for enantioconvergence and enantioselectivity control were discussed.

The enantioconvergent alkyl–alkyl coupling involves two competitive catalytic cycles with nickel(0) and nickel(i) active catalysts, respectively. K₃PO₄ plays a crucial role to enable the hydride transfer from hydrosilane to nickel–bromine species.     

Stress Relaxation Behaviors of Monocrystalline Silicon Coated with Amorphous SiO2 Film:A Molecular Dynamics Study

Long-lasting constant loading commonly exists in silicon-based microelectronic con-tact,as well as the chemical mechanical polishing area.In this work,the stres...     

Analysis of the Composition of Deinagkistrodon acutus Snake Venom Based on Proteomics,and Its Antithrombotic Activity and Toxicity Studies

There is a strong correlation between the composition of Deinagkistrodon acutus venom proteins and their potential pharmacological effects. The proteomic analysis revealed 103 proteins identified through label-free proteomics from 30 different snake venom families. Phospholipase A2 (30.0%), snaclec (21.0%), antithrombin (17.8%), thrombin (8.1%) and metalloproteinases (4.2%) were the most abundant proteins. The main toxicity of Deinagkistrodon acutus venom is hematotoxicity and neurotoxicity, and it acts on the lung. Deinagkistrodon acutus venom may have anticoagulant and antithrombotic effects. In summary, the protein profile and related toxicity and pharmacological activity of Deinagkistrodon acutus venom from southwest China were put forward for the first time. In addition, we revealed the relationship between the main toxicity, pharmacological effects, and the protein components of snake venom.     

Health-Promoting Properties of Medicinal Mushrooms and Their Bioactive Compounds for the COVID-19 Era—An Appraisal: Do the Pro-Health Claims Measure Up?

Many mushroom species are consumed as food, while significant numbers are also utilised medicinally. Mushrooms are rich in nutrients and bioactive compounds. A growing body of in vitro, in vivo, and human research has revealed their therapeutic potentials, which include such properties as anti-pathogenic, antioxidant, anti-inflammatory, immunomodulatory, gut microbiota enhancement, and angiotensin-converting enzyme 2 specificity. The uses of medicinal mushrooms (MMs) as extracts in nutraceuticals and other functional food and health products are burgeoning. COVID-19 presents an opportunity to consider how, and if, specific MM compounds might be utilised therapeutically to mitigate associated risk factors, reduce disease severity, and support recovery. As vaccines become a mainstay, MMs may have the potential as an adjunct therapy to enhance immunity. In the context of COVID-19, this review explores current research about MMs to identify the key properties claimed to confer health benefits. Considered also are barriers or limitations that may impact general recommendations on MMs as therapy. It is contended that the extraction method used to isolate bioactive compounds must be a primary consideration for efficacious targeting of physiological endpoints. Mushrooms commonly available for culinary use and obtainable as a dietary supplement for medicinal purposes are included in this review. Specific properties related to these mushrooms have been considered due to their potential protective and mediating effects on human exposure to the SARS CoV-2 virus and the ensuing COVID-19 disease processes.     

Numerical Study on the Coagulation and Breakage of Nanoparticles in the Two-Phase Flow around Cylinders

The Reynolds averaged N-S equation and dynamic equation for nanoparticles are numerically solved in the two-phase flow around cylinders, and the distributions of the concentration M₀ and geometric mean diameter d_g of particles are given. Some of the results are validated by comparing with previous results. The effects of particle coagulation and breakage and the initial particle concentration m₀₀ and size d₀ on the particle distribution are analyzed. The results show that for the flow around a single cylinder, M₀ is reduced along the flow direction. Placing a cylinder in a uniform flow will promote particle breakage. For the flow around multiple cylinders, the values of M₀ behind the cylinders oscillate along the spanwise direction, and the wake region in the flow direction is shorter than that for the flow around a single cylinder. For the initial monodisperse particles, the values of d_g increase along the flow direction and the effect of particle coagulation is larger than that of particle breakage. The values of d_g fluctuate along the spanwise direction; the closer to the cylinders, the more frequent the fluctuations of d_g values. For the initial polydisperse particles with d₀ = 98 nm and geometric standard deviation σ = 1.65, the variations of d_g values along the flow and spanwise directions show the same trend as for the initial monodisperse particles, although the differences are that the values of d_g are almost the same for the cases with and without considering particle breakage, while the distribution of d_g along the spanwise direction is flatter in the case with initial polydisperse particles.     

Efficient conversion of fructose to 5-hydroxymethylfurfural over sulfated porous carbon catalyst

Sulfated porous carbon (PC-SO3H) catalyst was successfully synthesized from one-pot treatment of porous polydivinylbenzene in H2SO4 at 250 C, which exhibited very good catalytic performances in the production of 5-hydroxymethylfurfural from fructose.