Prevalence and characteristics of rmtB and qepA in Escherichia coli isolated from diseased animals in China

16S rRNA methylase and QepA, a fluoroquinolone efflux pump, are new mechanisms of resistance against aminoglycosides and fluoroquinolone, respectively. One of 16S rRNA methylase genes, rmtB, was found to be associated with qepA, were both located on the same transposable element. In this study, we intended to determine the current prevalence and characteristics of the 16S rRNA methylase genes and qepA, and to study the association between rmtB and qepA. A total of 892 Escherichia coli isolates were collected from various diseased food-producing animals in China from 2004-2008 and screened by PCR for 16S rRNA methylase genes and qepA. About 12.6% (112/892) and 0.1% (1/892) of isolates that were highly resistant to amikacin were positive for rmtB and armA, respectively. The remaining five 16S rRNA methlyase genes were not detected. Thirty-six (4.0%) strains carried qepA. About 32.1% of rmtB-positive strains harbored qepA, which was not detected in rmtB-negative strains. Most strains were clonally unrelated, while identical PFGE profiles of rmtB-positive isolates were found in the same farm indicating clonal transmission. Conjugation experiments showed that rmtB was transfered to the recipients, and qepA also cotransfered with rmtB in some cases. The spread of E. coli of food animal origin harboring both rmtB and qepA suggests that surveillance for antimicrobial resistance of animal origin as well as the study of the mechanisms of resistance should be undertaken

Ezrin regulating the cytoskeleton remodelling is required for hypoxia-induced Myofibroblast proliferation and migration

Background: Hypoxia pulmonary arterial hypertension (HPAH) is a disease of the small vessels characterized by sustained vasoconstriction, thickening of arterial walls, vascular remodelling, and progressive increase in pulmonary vascular resistance, thus leading to right heart failure and finally death. Recent evidence demonstrated that massive Pulmonary Artery Smooth Muscle-like Cells (PASMLCs) accumulating in the intima might also be developed from the differentiation of Pulmonary Myofibroblast (PMF) of tunica media. And PMF appeared the phenomenon of the cytoskeleton remodeling. So, it would be important in the clarification of the pivotal factors controlling this cytoskeleton structure change. Methods: PMFs were cultured from the normal rats and then divided into three groups and incubated by nomal or hypoxic conditions respectively. mRNA level was evaluated by real time reverse transcription polymerase chain reaction, and protein expression was detected by western blot. Cell proliferation was determined by the MTT and thymidine incorporation assay. Results: Here, we report that the hypoxia increased the expression levels of Ezrin mRNA and protein in PMFs, which might explain the expression of cytoskeletal proteins (Destrin, a1-actin, and a1-tubulin) in PMFs was significantly induced by hypoxia. After inhibiting Ezrin in PMFs by siRNA transfection, we found the over-expression of cytoskeletal proteins induced by hypoixa were significantly suppressed at all time points. Additionally, we found that hypoxia or over-expression of Ezrin through Ad-Ezrin transfection significantly increases the proliferation and migration of PMFs, and which could be inverted by the transfection of siRNA. Conclusion: These findings suggest that Ezrin regulating of aberrant dysregulation of cytoskeletal proteins may be the major cause of PMFs' proliferation and migration under the condition of hypoxia and may, therefore, play a fundamental role in the accumulation of PASMLCs of HPAH

Predicting individual brain maturity using dynamic functional connectivity

Neuroimaging-based functional connectivity (FC) analyses have revealed significant developmental trends in specific intrinsic connectivity networks linked to cognitive and behavioral maturation. However, knowledge of how brain functional maturation is associated with FC dynamics at rest is limited. Here, we examined age-related differences in the temporal variability of FC dynamics with data publicly released by the Nathan Kline Institute (NKI) (n=183, ages 7-30) and showed that dynamic inter-region interactions can be used to accurately predict individual brain maturity across development. Furthermore, we identified a significant age-dependent trend underlying dynamic inter-network FC, including increasing variability of the connections between the visual network, default mode network (DMN) and cerebellum as well as within the cerebellum and DMN and decreasing variability within the cerebellum and between the cerebellum and DMN as well as the cingulo-opercular network. Overall, the results suggested significant developmental changes in dynamic inter-network interaction, which may shed new light on the functional organization of typical developmental brains

Prevalence of extended-spectrum cephalosporin-resistant Escherichia coli in a farrowing farm: ST1121 clone harboring IncHI2 plasmid contributes to the dissemination of blaCMY-2

Abstract During a regular monitoring of antimicrobial resistance in a farrowing farm in Southern China, 117 Escherichia coli isolates were obtained from sows and piglets. Compared with the isolates from piglets, the isolates from sows exhibited higher resistance rates to the tested cephalosporins. Correspondingly, the total detection rate of the blaCMY-2/blaCTX-M genes in the sow isolates (34.2%) was also significantly higher than that of the piglet isolates (13.6%) (p<0.05). The blaCMY-2 gene had a relatively high prevalence (11.1%) in the E. coli isolates. MLST and PFGE analysis revealed the clonal spread of ST1121 E. coli in most (7/13) of the blaCMY-2-positive isolates. An indistinguishable IncHI2 plasmid harboring blaCMY-2 was also identified in each of the seven ST1121 E. coli isolates. Complete sequence analysis of this IncHI2 plasmid (pEC5207) revealed that pEC5207 may have originated through recombination of an IncHI2 plasmid with a blaCMY-2-carrying IncA/C plasmid like pCFSAN007427_01. In addtion to blaCMY-2, pEC5207 also carried other resistance determinants for aminoglycosides (aacA7), sulfonamides (sul1), as well as heavy metals ions, such as Cu and Ag. The susceptibility testing showed that the pEC5207 can mediate both antibiotic and heavy metal resistance. This highlights the role of pEC5207 in co-selection of blaCMY-2-positive isolates under the selective pressure of heavy metals, cephalosporins and other antimicrobials. In conclusion, clonal spread of an ST1121 type E. coli strain harboring an IncHI2 plasmid contributed to the dissemination of blaCMY-2 in a farrowing farm in Southern China. We also have determined the first complete sequence analysis of a blaCMY-2-carrying IncHI2 plasmid

Expression of TaWRKY44, a wheat WRKY gene, in transgenic tobacco confers multiple abiotic stress tolerances

The WRKY transcription factors have been reported to be involved in various plant physiological and biochemical processes. In this study, we successfully assembled ten unigenes from expressed sequence tags (ESTs) of wheat and designated them as TaWRKY44–TaWRKY53, respectively. Among these genes, a subgroup I gene, TaWRKY44, was found to be upregulated by treatments with PEG6000, NaCl, 4°C, abscisic acid (ABA), H2O2 and gibberellin (GA). The TaWRKY44-GFP fusion protein was localized to the nucleus of onion epidermal cells, and TaWRKY44 was able to bind to the core DNA sequences of TTGACC and TTAACC in yeast. The N-terminal of TaWRKY44 showed transcriptional activation activity. Expression of TaWRKY44 in tobacco plants conferred drought and salt tolerance and transgenic tobacco exhibited a higher survival rate, relative water content (RWC), soluble sugar, proline and superoxide dismutase (SOD) content, as well as higher activities of catalase (CAT) and peroxidase (POD), but less ion leakage (IL), lower contents of malondialdehyde (MDA), and H2O2. In addition, expression of TaWRKY44 also increased the seed germination rate in the transgenic lines under osmotic stress conditions while exhibiting a lower H2O2 content and higher SOD, CAT and POD activities. Expression of TaWRKY44 upregulated the expression of some reactive oxygen species (ROS)-related genes and stress-responsive genes in tobacco under osmotic stresses. These data demonstrate that TaWRKY44 may act as a positive regulator in drought/salt/osmotic stress responses by either efficient ROS elimination through direct or indirect activation of the cellular antioxidant systems or activation of stress-associated gene expression