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The tumor suppressor gene phosphatase and tensin homolog (PTEN) in PI3K/Akt/mTOR pathway is essential in inhibiting tumor growth and metastasis. However, whether the mutation of PTEN gene could induce tumorigenesis and impact the treatment of gastric cancer is still unclear. The purpose of the study was to investigate the combined treatment of gastric tumorigenesis using Rapamycin and Fluorouracil (5-Fu) through interfering with the Akt/mTOR pathway in a mouse model with PTEN conditional deletion. Three groups of mice were exposed for 5 days to Rapamycin and 5-Fu separately and together. The gene expression of the Akt/mTOR pathway, the protein expression of caspase-3 and p-Akt, p-S6K and p-4EBP1, and the pathological changes in stomachs were analyzed. Our study demonstrates that the conditional PTEN deletion in the cells of glandular stomach induces hyperplastic gastric tumors in mice. The combined Rapamycin administration with 5-Fu resulted in better outcomes than their separate administration for the treatment of gastric cancer by inhibiting the mTOR signal pathway. Our study indicates that Rapamycin has a synergistic interaction with chemotherapeutic 5-Fu, and demonstrates a potential therapeutic combination treatment on glandular stomach tumor with PTEN functional absence or aberrantly activated Akt/mTOR pathway. It provides important insights into the inhibition of the Akt/mTOR pathway in gastric cancer clinical therapy. [ABSTRACT FROM AUTHOR]

Sexual dimorphism is widespread in fish species. The red-tail catfish (Mystus wyckioides) is a commercially important catfish in the lower reaches of the Lancang River and the Mekong basin, and it shows a growth advantage in males. Here, RNA-seq was for the first time used to explore the gene expression difference between the sexes in the hypothalamus and pituitary of red-tail catfish, respectively. In the hypothalamus, 5732 and 271 unigenes have significantly higher and lower expressions, respectively, in males compared with females. KEGG analysis showed that 212 DEGs were annotated to 216 signaling pathways, and enrichment analysis suggested different levels of cAMP and glutamatergic synapse signaling between male and female hypothalami and some of the DEGs appear involved in gonad development and growth. In the pituitary, we found only 19 differentially expressed unigenes, which were annotated to 32 signaling pathways, most of which play important roles in gonad development. [ABSTRACT FROM AUTHOR]

A novel high-performance non-noble metal electrocatalyst for the oxygen reduction reaction (ORR) was fabricated by anchoring cobalt tetraferrocenylporphyrin (CoFcP) onto poly(sodium- p-styrenesulfonate) modified graphene (PSS-Gr) through solvothermally assisted π-π assembling method. The morphology of the assembled composite was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The interactions between CoFcP moieties and graphene sheets were confirmed by UV-Vis absorption spectroscopy and X-ray photoelectron spectroscopy. The electrocatalytic properties of the CoFcP/PSS-Gr catalyst towards the oxygen reduction reaction were assessed using rotating disk electrode (RDE) and rotating ring-disk electrode (RRDE) measurements in both alkaline and acidic media. In addition, cyclic voltammetry and chronoamperometric measurements were utilized to evaluate the catalytic activity and stability of the CoFcP/PSS-Gr composite in alkaline solution. The results showed that CoFcP supported on graphene exhibited an outstanding electrocatalytic performance towards the ORR comparable with commercial Pt/C catalyst in alkaline media, such as high onset potential (0.889 V vs. reversible hydrogen electrode, RHE), half wave potential (0.789 V vs. RHE), better tolerance to methanol, excellent stability (84.1 %, retention after 10000 s), and efficient four-electron pathway. Moreover, the proposed hybrid presented excellent catalytic activity in terms of onset potential (0.72 V vs. RHE) and high-electron transfer number compared with Pt/C in acidic media. [ABSTRACT FROM AUTHOR]

In this paper, we present a two-step covalent modification approach to fabricate a novel nitrite sensor through anchoring nickel-tetrahydroxy-phthalocyanine (NiPc(OH)) and polyethylene oxide (PEO) onto a glassy carbon electrode (GCE). The surface morphology of the prepared NiPc(OH)/PEO composite films under different dry conditions was characterized by scanning electron microscopy (SEM). The electrochemical behavior of NiPc(OH)/PEO composite film modified GCE toward the catalytic oxidation of nitrite in pH 7.0 phosphate buffer solution (PBS) was investigated by cyclic voltammetry (CV). After drying under an infrared lamp, the fabricated sensor showed a pronounced electrocatalytic activity improvement toward the oxidation of nitrite and led to a significant decrease in the anodic overpotentials compared with bare GCE, which should be ascribed to the synergistic effect of NiPc(OH) and PEO, as well as the enlarged electrochemical effective surface area after drying. Using differential pulse voltammetry (DPV), the sensor gave a linear response to nitrite over the concentration range of 0.1-5,300 μM, with a detection limit of 0.0522 μM. The nitrite sensor exhibits good sensitivity, selectivity, and stability and has been applied for the determination of nitrite in water samples. [ABSTRACT FROM AUTHOR]

The novel covalently modified glassy carbon electrode with poly(xylitol) was prepared using an electropolymerization technique for the simultaneous determination of uric acid (UA), xanthine (XA) and hypoxanthine (HX). This new electrode presents an excellent electrocatalytic activity towards the oxidation of UA, XA and HX by cyclic voltammetry (CV) method. The oxidation peaks of the three compounds were well defined and had enhanced the peak currents. The separation potentials of the oxidation peak potentials for UA-XA and XA-HX were 380 and 370 mV in CV, respectively. Using differential pulse voltammetry (DPV) method, the calibration curves in the ranges of 5-55, 1.3-75.3 and 4-59 μmol/L were obtained for HX, XA and UA, respectively. The lowest detection limits (S/N=3) were 4.5, 0.75 and 3.75 μmol/L for HX, XA and UA, respectively. The practical application of the modified electrode was demonstrated by the determination of UA, XA, HX in human urine samples. [ABSTRACT FROM AUTHOR]

Various chloroplast transit peptides (CTP) have been used to successfully target some foreign proteins into chloroplasts, but for other proteins these same CTPs have reduced localization efficiencies or fail completely. The underlying cause of the failures remains an open question, and more effective CTPs are needed. In this study, we initially observed that two E.coli enzymes, EcTSR and EcGCL, failed to be targeted into rice chloroplasts by the commonly-used rice rbcS transit peptide (rCTP) and were subsequently degraded. Further analyses revealed that the N-terminal unfolded region of cargo proteins is critical for their localization capability, and that a length of about 20 amino acids is required to attain the maximum localization efficiency. We considered that the unfolded region may alleviate the steric hindrance produced by the cargo protein, by functioning as a spacer to which cytosolic translocators can bind. Based on this inference, an optimized CTP, named RC2, was constructed. Analyses showed that RC2 can more effectively target diverse proteins, including EcTSR and EcGCL, into rice chloroplasts. Collectively, our results provide further insight into the mechanism of CTP-mediated chloroplastic localization, and more importantly, RC2 can be widely applied in future chloroplastic metabolic engineering, particularly for crop plants. [ABSTRACT FROM AUTHOR]