Fluorometric sensing of pH values using green-emitting black phosphorus quantum dots.

A fluorometric method is described for "turn-on" sensing of pH values via black phosphorus quantum dots (BPQD). Water-stable BPQD were synthesized by a liquid exfoliation method and characterized by TEM, FT-IR, XPS, and absorption and fluorescence spectra. The nanoparticles of BPQD have a uniform distribution with an average size of 5.2 nm. They exhibit bright green fluorescence, with excitation/emission maxima at 420/515 nm. The fluorescence of the BPQD is likely to arise from the quasi-molecular fluorophores of polycyclic aromatic compounds carrying P-P, P-O-P, and PxOy functions on its surface. The protonation and deprotonation of hydroxyl groups of BPQD causes a different degree of quenching of the BPQD. At pH values below 4.0, protons bind to BPQD to form non-fluorescent ground state complexes. At pH values above 4.0, the hydroxyl groups become deprotonated, and this induces the recovery of fluorescence. The sensor has a linear response in the pH range of 1.0-9.0. It was successfully applied to the determination of the pH values in human urine and serum samples. Graphical abstract Schematic representation of the preparation of black phosphorus quantum dots (BPQDs) from powdered BP crystals using liquid-phase exfoliation in N-methyl-2-pyrrolidone solution. The BPQDs display green fluorescence at high pH values but no fluorescence at very low pH values.

Successful Treatment of Severe Toxic Hepatitis and Encephalopathy Without Respiratory Failure Caused by Paraquat Intoxication.

Lung damage is a characteristic feature of paraquat intoxication; most deaths resulting from ingesting paraquat are due to progressive respiratory failure. Liver failure caused by paraquat intoxication is rare. A case of orally ingested paraquat intoxication is reported in which serious liver injury and toxic encephalopathy were observed, but little lung damage was found. The principal systemic symptom was severe liver injury, characterized by cholestasis, that gradually became aggravated. In addition to standard treatment, aggressive treatment through liver protection and cholestasis was administered. Finally, liver function returned to normal and central nervous system symptoms were controlled. The patient was successfully discharged. This case suggests that the hepatotoxicity of paraquat intoxication is possibly characterized by cholestasis, and the treatment of cholestasis promotes recovery of severe hepatocyte damage.

Phosphoproteins regulated by heat stress in rice leaves.

BACKGROUND: High temperature is a critical abiotic stress that reduces crop yield and quality. Rice (Oryza sativa L.) plants remodel their proteomes in response to high temperature stress. Moreover, phosphorylation is the most common form of protein post-translational modification (PTM). However, the differential expression of phosphoproteins induced by heat in rice remains unexplored. METHODS: Phosphoprotein in the leaves of rice under heat stress were displayed using two-dimensional electrophoresis (2-DE) and Pro-Q Diamond dye. Differentially expressed phosphoproteins were identified by MALDI-TOF-TOF-MS/MS and confirmed by Western blotting. RESULTS: Ten heat-phosphoproteins were identified from twelve protein spots, including ribulose bisphos-phate carboxylase large chain, 2-Cys peroxiredoxin BAS1, putative mRNA binding protein, Os01g0791600 protein, OSJNBa0076N16.12 protein, putative H(+)-transporting ATP synthase, ATP synthase subunit beta and three putative uncharacterized proteins. The identification of ATP synthase subunit beta was further validated by Western-blotting. Four phosphorylation site predictors were also used to predict the phosphorylation sites and the specific kinases for these 10 phosphoproteins. CONCLUSION: Heat stress induced the dephosphorylation of RuBisCo and the phosphorylation of ATP-ß, which decreased the activities of RuBisCo and ATP synthase. The observed dephosphorylation of the mRNA binding protein and 2-Cys peroxiredoxin may be involved in the transduction of heat-stress signaling, but the functional importance of other phosphoproteins, such as H+-ATPase, remains unknown.

PhosphoRice: a meta-predictor of rice-specific phosphorylation sites.

BACKGROUND: As a result of the growing body of protein phosphorylation sites data, the number of phosphoprotein databases is constantly increasing, and dozens of tools are available for predicting protein phosphorylation sites to achieve fast automatic results. However, none of the existing tools has been developed to predict protein phosphorylation sites in rice. RESULTS: In this paper, the phosphorylation site predictors, NetPhos 2.0, NetPhosK, Kinasephos, Scansite, Disphos and Predphosphos, were integrated to construct meta-predictors of rice-specific phosphorylation sites using several methods, including unweighted voting, unreduced weighted voting, reduced unweighted voting and weighted voting strategies. PhosphoRice, the meta-predictor produced by using weighted voting strategy with parameters selected by restricted grid search and conditional random search, performed the best at predicting phosphorylation sites in rice. Its Matthew's Correlation Coefficient (MCC) and Accuracy (ACC) reached to 0.474 and 73.8%, respectively. Compared to the best individual element predictor (Disphos_default), PhosphoRice archieved a significant increase in MCC of 0.071 (P < 0.01), and an increase in ACC of 4.6%. CONCLUSIONS: PhosphoRice is a powerful tool for predicting unidentified phosphorylation sites in rice. Compared to the existing methods, we found that our tool showed greater robustness in ACC and MCC. PhosphoRice is available to the public at http://bioinformatics.fafu.edu.cn/PhosphoRice.