Three kinds of plasmid-mediated quinolone resistance (PMQR) determinants have been discovered and have been shown to be widely distributed among clinical isolates: qnr genes, aac(6)-Ib-cr, and qepA. Few data on the prevalence of these determinants in strains from animals are available. The presence of PMQR genes in isolates from animals was determined by PCR amplification and DNA sequencing. The production of extended-spectrum ␤-lactamases (ESBLs) and AmpC ␤-lactamases in the strains was detected, and their genotypes were determined. The genetic environment of PMQR determinants in selected plasmids was analyzed. All samples of ceftiofur-resistant (MICs > 8 g/ml) isolates of the family Enterobacteriaceae were selected from 36 companion animals and 65 food-producing animals in Guangdong Province, China, between November 2003 and April 2007, including 89 Escherichia coli isolates, 9 Klebsiella pneumoniae isolates, and isolates of three other genera. A total of 68.3% (69/101) of the isolates produced ESBLs and/or AmpC ␤-lactamases, mainly those of the CTX-M and CMY types. Of the 101 strains, PMQR determinants were present in 35 (34.7%) isolates, with qnr, aac(6)-Ib-cr, and qepA detected alone or in combination in 8 (7.9%), 19 (18.8%), and 16 (15.8%) strains, respectively. The qnr genes detected included one qnrB4 gene, four qnrB6 genes, and three qnrS1 genes. Five strains were positive for both aac(6)-Ib-cr and qepA, while one strain was positive for qnrS1, aac(6)-Ib-cr, and qepA. qnrB6 was flanked by two copies of ISCR1 with an intervening dfr gene downstream and sul1 and qacE⌬1 genes upstream. In another plasmid, aac(6)-Ib-cr followed intI1 and arr-3 was downstream. PMQR determinants are highly prevalent in ceftiofur-resistant Enterobacteriaceae strains isolated from animals in China. This is the first report of the occurrence of PMQR determinants among isolates from companion animals.

Angiotensin II (Ang II) stimulates norepinephrine transporter (NET) and tyrosine hydroxylase (TH) in the neurons, but the signal transduction mechanism of this neuromodulation is not understood. Treatment of neuronal cultures of hypothalamusbrainstem with Ang II resulted in a time-and dose-dependent activation of Ras, Raf-1, and mitogen-activated protein kinase. This activation was mediated by the interaction of Ang II with the AT 1 receptor subtype and was associated with the redistribution of AT 1 receptor with Ras and Raf-1 on the neuronal membrane. Treatment with antisense oligonucleotide (AON) to mitogen-activated protein kinase decreased mitogen-activated protein kinase immunoreactivity by 70% and attenuated Ang II stimulation of c-fos, NET, and TH mRNA levels. This demonstrates that induction of these genes requires mitogenactivated protein kinase activation by Ang II. In contrast, AON to mitogen-activated protein kinase failed to inhibit Ang II stimulation of plasminogen activator inhibitor-1 mRNA levels. These results suggest that AT 1 receptors are coupled to a Ras-Raf-1 mitogen-activated protein kinase signal transduction pathway that is responsible for stimulation of NET and TH, two neuromodulatory actions of Ang II in the brain.

BackgroundResveratrol is a natural polyphenolic compound that has cardioprotective, anticancer and anti-inflammatory properties. We investigated the capacity of resveratrol to protect RAW 264.7 cells from inflammatory insults and explored mechanisms underlying inhibitory effects of resveratrol on RAW 264.7 cells.Methodology/Principal FindingsMurine RAW 264.7 cells were treated with resveratrol (1, 5, and 10 µM) and/or LPS (5 µg/ml). Nitric oxide (NO) and prostaglandin E2 (PGE2) were measured by Griess reagent and ELISA. The mRNA and protein levels of proinflammatory proteins and cytokines were analysed by ELISA, RT-PCR and double immunofluorescence labeling, respectively. Phosphorylation levels of Akt, cyclic AMP-responsive element-binding protein (CREB), mitogen-activated protein kinases (MAPKs) cascades, AMP-activated protein kinase (AMPK) and expression of SIRT1(Silent information regulator T1) were measured by western blot. Wortmannin (1 µM), a specific phosphatidylinositol 3-kinase (PI3-K) inhibitor, was used to determine if PI3-K/Akt signaling pathway might be involved in resveratrol’s action on RAW 264.7 cells. Resveratrol significantly attenuated the LPS-induced expression of nitric oxide (NO), prostaglandin E2 (PGE2), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in RAW 264.7 cells. Resveratrol increased Akt phosphorylation in a time-dependent manner. Wortmannin, a specific phosphatidylinositol 3-kinase (PI3-K) inhibitor, blocked the effects of resveratrol on LPS-induced RAW 264.7 cells activation. In addition, PI3-K inhibition partially abolished the inhibitory effect of resveratrol on the phosphorylation of cyclic AMP-responsive element-binding protein (CREB) and mitogen-activated protein kinases (MAPKs) cascades. Meanwhile, PI3-K is essential for resveratrol-mediated phosphorylation of AMPK and expression of SIRT1.Conclusion and ImplicationsThis investigation demonstrates that PI3-K/Akt activation is an important signaling in resveratrol-mediated activation of AMPK phosphorylation and SIRT1 expression, and inhibition of phosphorylation of CREB and MAPKs activation, proinflammatory mediators and cytokines production in response to LPS in RAW 264.7 cells.

BackgroundMicroglial activation plays an important role in neurodegenerative diseases by producing several proinflammatory enzymes and proinflammatory cytokines. The phenolic glucoside gastrodin, a main constituent of a Chinese herbal medicine, has been known to display anti-inflammatory properties. The current study investigates the potential mechanisms whereby gastrodin affects the expression of potentially pro-inflammatory proteins by cultured murine microglial BV-2 cells stimulated with lipopolysaccharide (LPS).Methodology/Principal FindingsBV-2 cells were pretreated with gastrodin (30, 40, and 60 µM) for 1 h and then stimulated with LPS (1 µg/ml) for another 4 h. The effects on proinflammatory enzymes, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), and proinflammatory cytokines, tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β), are analysed by double-immunofluorescence labeling and RT-PCR assay. To reveal the mechanisms of action of gastrodin we investigated the involvement of mitogen-activated protein kinases (MAPKs) cascades and their downstream transcription factors, nuclear factor-κB (NF-κB) and cyclic AMP-responsive element (CRE)-binding protein (CREB). Gastrodin significantly reduced the LPS-induced protein and mRNA expression levels of iNOS, COX-2, TNF-α, IL-1β and NF-κB. LPS (1 µg/ml, 30 min)-induced phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal protein kinase (JNK) and p38 mitogen-activated protein kinase (p38 MAPK) and this was inhibited by pretreatment of BV-2 cells with different concentrations of gastrodin (30, 40, and 60 µM). In addition, gastrodin blocked LPS-induced phosphorylation of inhibitor κB-α (IκB-α) (and hence the activation of NF-κB) and of CREB, respectively.Conclusion and ImplicationsThis study indicates that gastrodin significantly attenuate levels of neurotoxic proinflammatory mediators and proinflammatory cytokines by inhibition of the NF-κB signaling pathway and phosphorylation of MAPKs in LPS-stimulated microglial cells. Arising from the above, we suggest that gastrodin has a potential as an anti-inflammatory drug candidate in neurodegenerative diseases.