The aim of this study was to evaluate the activity of marbofloxacin and establish the optimal dose regimens for decreasing the development of fluoroquinolone resistance in pigs against Escherichia coli with ex vivo pharmacokinetic/pharmacodynamic (PK/PD) modeling. The recommended dose (2 mg/kg body weight) of marbofloxacin was orally administered in healthy pigs. The ileum content and plasma were both collected for the determination of marbofloxacin. The main parameters of Cmax, AUC0-24 h, AUC, Ke, t1/2ke, MRT and Clb were 11.28 μg/g, 46.15, 77.81 μg⋅h/g, 0.001 h-1, 69.97 h, 52.45 h, 0.026 kg/h in ileum content, and 0.55 μg/ml, 8.15, 14.67 μg⋅h/ml, 0.023 h-1, 30.67 h, 34.83 h, 0.14 L/h in plasma, respectively In total, 218 E. coli strains were isolated from most cities of China. The antibacterial activity in vitro and ex vivo of marbofloxacin against E. coli was determined following CLSI guidance. The MIC90 of sensitive strains (142) was calculated as 2 μg/ml. The minimum inhibitory concentration (MIC) of HB197 was 2 and 4 μg/ml in broth and ileum fluids, respectively. In vitro mutant prevention concentration, growth and killing-time in vitro and ex vivo of marbofloxacin against selected HB197 were assayed for pharmacodynamic studies. According to the inhibitory sigmoid Emax modeling, the value of AUC0-24 h/MIC produced in ileum content was achieved, and bacteriostatic, bactericidal activity, and elimination were calculated as 16.26, 23.54, and 27.18 h, respectively. Based on Monte Carlo simulations to obtain 90% target attainment rate, the optimal doses to achieve bacteriostatic, bactericidal, and elimination effects were 0.85, 1.22, and 1.41 mg/kg.bw for 50% target, respectively, and 0.92, 1.33, and 1.53 mg/kg.bw for 90% target, respectively, after oral administration. The results in this study provided a more optimized alternative for clinical use and demonstrated that the dosage 2 mg/kg of marbofloxacin by oral administration could have an effect on bactericidal activity against E. coli.

Research on neuropeptide function has advanced rapidly, yet there is still no spatio-temporally resolved method to measure the release of neuropeptides in vivo. Here we introduce Neuropeptide Release Reporters (NPRRs): novel genetically-encoded sensors with high temporal resolution and genetic specificity. Using the Drosophila larval neuromuscular junction (NMJ) as a model, we provide evidence that NPRRs recapitulate the trafficking and packaging of native neuropeptides, and report stimulation-evoked neuropeptide release events as real-time changes in fluorescence intensity, with sub-second temporal resolution.

The current study was conducted to evaluate the antibacterial combination efficacies, and whether the sub-inhibitory concentrations (sub-MIC) of antibiotics can influent on the biofilm formation of S. aureus. The minimum inhibitory concentration (MIC) of common antibacterial drugs was determined in vitro against clinical isolates of Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Pasteurella multocida (P. multocida) alone and in combination with each other by using the broth microdilution method and the checkerboard micro-dilution method analyzed with the fractional inhibitory concentration index (FICI), respectively. Regarding these results, antibacterial drug combinations were categorized as synergistic, interacting, antagonistic and indifferent, and most of the results were consistent with the previous reports. Additionally, the effects of sub-MIC of seven antimicrobials (kanamycin, acetylisovaleryltylosin tartrate, enrofloxacin, lincomycin, colistin sulfate, berberine, and clarithromycin) on S. aureus biofilm formation were determined via crystal violet staining, scanning electron microscopy (SEM) and real-time PCR. Our results demonstrate that all antibiotics, except acetylisovaleryltylosin tartrate, effectively reduced the S. aureus biofilm formation. In addition, real-time reverse transcriptase PCR was used to analyze the relative expression levels of S. aureus biofilm-related genes such as sarA, fnbA, rbf, lrgA, cidA, and eno after the treatment at sub-MIC with all of the six antimicrobials. All antibiotics significantly inhibited the expression of these biofilm-related genes except for acetylisovaleryltylosin tartrate, which efficiently up-regulated these transcripts. These results provide the theoretical parameters for the selection of effective antimicrobial combinations in clinical therapy and demonstrate how to correctly use antibiotics at sub-MIC as preventive drugs.

Influenza A virus (IAV) must utilize the host cell machinery to replicate, but many of the mechanisms of IAV-host interaction remain poorly understood. Improved understanding of interactions between host factors and vRNP not only increases our basic knowledge of the molecular mechanisms of virus replication and pathogenicity but also provides insights into possible novel antiviral targets that are necessary due to the widespread emergence of drug-resistant IAV strains. Here, we have identified LYAR, a cell growth-regulating nucleolar protein, which interacts with viral RNP components and is important for efficient replication of IAVs and whose role in the IAV life cycle has never been reported. In addition, we further reveal the role of LYAR in viral RNA synthesis. Our results extend and improve current knowledge on the mechanisms of IAV transcription and replication.

Arctigenin (ARG) has been previously reported to exert high biological activities including anti-inflammatory, antiviral and anticancer. In this study, the anti-tumor mechanism of ARG towards human hepatocellular carcinoma (HCC) was firstly investigated. We demonstrated that ARG could induce apoptosis in Hep G2 and SMMC7721 cells but not in normal hepatic cells, and its apoptotic effect on Hep G2 was stronger than that on SMMC7721. Furthermore, the following study showed that ARG treatment led to a loss in the mitochondrial out membrane potential, up-regulation of Bax, down-regulation of Bcl-2, a release of cytochrome c, caspase-9 and caspase-3 activation and a cleavage of poly (ADP-ribose) polymerase in both Hep G2 and SMMC7721 cells, suggesting ARG-induced apoptosis was associated with the mitochondria mediated pathway. Moreover, the activation of caspase-8 and the increased expression levels of Fas/FasL and TNF-α revealed that the Fas/FasL-related pathway was also involved in this process. Additionally, ARG induced apoptosis was accompanied by a deactivation of PI3K/p-Akt pathway, an accumulation of p53 protein and an inhibition of NF-κB nuclear translocation especially in Hep G2 cells, which might be the reason that Hep G2 was more sensitive than SMMC7721 cells to ARG treatment.