An Escherichia coli O157:H7 outbreak in China in 1999 caused 177 deaths due to hemolytic uremic syndrome. Sixteen outbreak associated isolates were found to belong to a new clone, sequence type 96 (ST96), based on multilocus sequence typing of 15 housekeeping genes. Whole genome sequencing of an outbreak isolate, Xuzhou21, showed that the isolate is phylogenetically closely related to the Japan 1996 outbreak isolate Sakai, both of which share the most recent common ancestor with the US outbreak isolate EDL933. The levels of IL-6 and IL-8 of peripheral blood mononuclear cells induced by Xuzhou21 and Sakai were significantly higher than that induced by EDL933. Xuzhou21 also induced a significantly higher level of IL-8 than Sakai while both induced similar levels of IL-6. The expression level of Shiga toxin 2 in Xuzhou21 induced by mitomycin C was 68.6 times of that under non-inducing conditions, twice of that induced in Sakai (32.7 times) and 15 times higher than that induced in EDL933 (4.5 times). Our study shows that ST96 is a novel clone and provided significant new insights into the evolution of virulence of E. coli O157:H7.

Cry1Ab is one of the most common Bacillus thuringiensis (Bt) proteins in genetically modified crops, which exhibits strong resistance against insect pests. In the present study, a sensitive and precise liquid chromatography stable isotope dilution multiple reaction monitoring tandem mass spectrometry (LC-SID-MRM-MS) assay was developed and validated to quantify the amount of Cry1Ab expression in transgenic maize leaves. The measurement of protein was converted to measurement of unique peptides to Cry1Ab protein. Two peptides unique to Cry1Ab were synthesized and labeled in H(2)(18)O to generate (18)O stable isotope peptides as internal standards. The validated method obtained superior specificity and good linearity. And the inter- and intra-day precision and accuracy for all samples were satisfactory. The results demonstrated Cry1Ab protein was 31.7 ± 4.1 μg g(-1) dry weight in Bt-176 transgenic maize leaves. It proved that the novel LC-SID-MRM-MS method was sensitive and selective to quantify Cry1Ab in the crude extract without time-consuming pre-separation or purification procedures.

Although an abundant amount of research has been devoted to the studies of angiogenesis, its precise mechanisms are incompletely understood. Numerous clinical trials focused on therapeutic angiogenesis for the treatment of tissue ischemia have not been as successful as those of preclinical studies. Thus, additional studies are needed to better understand critical molecular mechanisms regulating ischemic neovascularization to identify novel therapeutic agents. Nitric oxide (NO) plays a central role in ischemic neovascularization through generation of cyclic guanosine monophosphate (cGMP) and activation of several other signalling responses. Accumulated evidence suggests that endothelial protein kinase A/endothelial nitric oxide synthase (PKA/eNOS) signalling may play an important role in ischemic disorders by promoting neovascularization. This review highlights recent advances in the role of PKA/eNOS and NO-cGMP-kinase cascade pathway in ischemic neovascularization. We also discuss molecular relationships of PKA/eNOS with other angiogenic pathways and explore the possibility of activation of the NO/nitrite endocrine system as potential therapeutic targets for ischemic angiogenesis.

Digital flexor tendon repair poses a significant challenge for hand surgeons. Currently, extrasynovial tendon grafts are frequently used in clinical settings to bridge flexor tendon defects. However, the healing process is always accompanied by postoperative adhesion. This is mostly due to the fact that no synovial membrane covers the extrasynovial tendon surface, in contrast to the intrasynovial tendon. In this study, we present an efficient method of developing a functional synovial biomembrane on the surface of the extrasynovial tendon. Synoviocytes were isolated from the knee joint of a Japanese white rabbit. After being infected with lentivirus, the over-expression of synoviolin in these synoviocytes was confirmed by semi-quantitative RT-PCR and western blotting. Cellular proliferation and increased hyaluronic acid secretion were confirmed in the synoviolin over-expressing synoviocytes by MTT-based method, cell cycle assays and ELISA. Furthermore, the synoviolin over-expressing synoviocytes were co-cultured with extrasynovial tendons that were harvested from the hind leg of rabbits. After being co-cultured in vitro for 3 and 7 days, these infected synoviocytes were found to accelerate the formation of a biomembrane on the tendon surface compared to the control group. More importantly, Alcian blue staining confirmed the ability of this cultured biomembrane to produce specific matrices containing acidic carboxyl mucopolysaccharides (mainly hyaluronic acid). All these results demonstrate that the over-expression of synoviolin stimulates the proliferation and HA secretion of synoviocytes and facilitates the formation of a functional synovial biomembrane. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.

Asp(299)Gly (D299G) and, to a lesser extent, Thr(399)Ile (T399I) TLR4 polymorphisms have been associated with Gram-negative sepsis and other infectious diseases, but the mechanisms by which they affect TLR4 signaling are unclear. In this study, we determined the impact of the D299G and T399I polymorphisms on TLR4 expression, interactions with myeloid differentiation factor 2 (MD2), LPS binding, and LPS-mediated activation of the MyD88- and Toll/IL-1R resistance domain-containing adapter inducing IFN-β (TRIF) signaling pathways. Complementation of human embryonic kidney 293/CD14/MD2 transfectants with wild-type (WT) or mutant yellow fluorescent protein-tagged TLR4 variants revealed comparable total TLR4 expression, TLR4-MD2 interactions, and LPS binding. FACS analyses with anti-TLR4 Ab showed only minimal changes in the cell-surface levels of the D299G TLR4. Cells transfected with D299G TLR4 exhibited impaired LPS-induced phosphorylation of p38 and TANK-binding kinase 1, activation of NF-κB and IFN regulatory factor 3, and induction of IL-8 and IFN-β mRNA, whereas T399I TLR4 did not cause statistically significant inhibition. In contrast to WT TLR4, expression of the D299G mutants in TLR4(-/-) mouse macrophages failed to elicit LPS-mediated induction of TNF-α and IFN-β mRNA. Coimmunoprecipitation revealed diminished LPS-driven interaction of MyD88 and TRIF with the D299G TLR4 species, in contrast to robust adapter recruitment exhibited by WT TLR4. Thus, the D299G polymorphism compromises recruitment of MyD88 and TRIF to TLR4 without affecting TLR4 expression, TLR4-MD2 interaction, or LPS binding, suggesting that it interferes with TLR4 dimerization and assembly of intracellular docking platforms for adapter recruitment.

Citrobacter freundii is an infrequent but established cause of diarrhea in humans. However, little is known of its genetic diversity and potential for virulence. We analyzed 26 isolates, including 12 from human diarrheal patients, 2 from human fecal samples of unknown diarrheal status, and 12 from animals, insects, and other sources. Pulsed field gel electrophoresis using XbaI allowed us to divide the 26 isolates into 20 pulse types, while multi-locus sequence typing using 7 housekeeping genes allowed us to divide the 26 isolates into 6 sequence types (STs) with the majority belonging to 4 STs. We analyzed adhesion and cytotoxicity to HEp-2 cells in these 26 strains. All were found to adhere to HEp-2 cells. One strain, CF74, which had been isolated from a goat, showed the strongest aggregative adhesion pattern. Lactate dehydrogenase (LDH) released from HEp-2 cells was evaluated as a measure of cytotoxicity, averaging 7.46%. Strain CF74 induced the highest level of LDH, 24.3%, and caused >50% cell rounding, detachment, and death. We named strain CF74 "cytotoxic and aggregative C. freundii." Genome sequencing of CF74 revealed that it had acquired 7 genomic islands, including 2 fimbriae islands and a type VI secretion system island, all of which are potential virulence factors. Our results show that aggregative adherence and cytotoxicity play an important role in the pathogenesis of C. freundii.

An original ultrasound (US) directly intensified photocatalytic reactor was designed to degrade azo dye pollutant methyl orange (MeO) using Degussa TiO(2) as the photocatalyst. The sonolytic, photocatalytic and sonophotocatalytic degradation of MeO in the new reactor and the synergistic effect between sonolysis and photocatalysis were investigated. Effects of operation parameters i.e., US power, TiO(2) dosage, liquid circulation velocity and air flow rate on degradation efficiency were investigated and optimized. The results showed that all parameters have optimal values for the sonophotocatalytic degradation of MeO, and the optimum conditions for the new process are US power 600W, TiO(2) dosage 3g/L, liquid circulation velocity 4.05×10(-2)m/s and air flow rate 0.2L/min. Under the optimum conditions, 91.52% MeO had been degraded within 1h, and the combination of sonolysis and TiO(2) photocatalysis exhibited an obvious synergetic effect.

An exopolysaccharide (EPS) producing strain was isolated from Tibetan kefir grains in China, which was identified by 16S rDNA tests and designated as Streptococcus thermophilus 05-34. The high-performance liquid chromatography analysis showed that it was composed of galactose and glucose in a molar ratio of 1.0:0.8 with a molecular mass of 2.5 × 10(4) Da. EPS was further revealed to have α-d-glucose, α-d-galactose, β-d-glucose, and β-d-galactose by Fourier transform infrared spectroscopy combined with 1D (1) H nuclear magnetic resonance spectroscopy. The length of EPS ranged from 10 to 100 nm and the maximal height of lumps was 2.5 nm through atomic force micrograph analysis. Furthermore, yogurt fermented with EPS-producing S. thermophilus 05-34 exhibited lower susceptibility to whey separation, higher viscosity, and sensory scores than those made with non-EPS-producing strain in yogurt production. These results suggested that EPS-producing Streptococcus thermophilus 05-34 provided a potential application in the fermented dairy industry.

BACKGROUND A major mechanism of translational regulation in response to a variety of stresses is mediated by phosphorylation of eIF2α to reduce delivery of initiator tRNAs to scanning ribosomes. For some mRNAs, often encoding a bZIP transcription factor, eIF2α phosphorylation leads to enhanced translation due to delayed reinitiation at upstream open reading frames. Dictyostelium cells possess at least three eIF2α kinases that regulate various portions of the starvation-induced developmental program. Cells possessing an eIF2α that cannot be phosphorylated (BS167) show abnormalities in growth and development. We sought to identify a bZIP protein in Dictyostelium whose production is controlled by the eIF2α regulatory system. PRINCIPAL FINDINGS Cells disrupted in the bzpR gene had similar developmental defects as BS167 cells, including small entities, stalk defects, and reduced spore viability. β-galactosidase production was used to examine translation from mRNA containing the bzpR 5' UTR. While protein production was readily apparent and regulated temporally and spatially in wild type cells, essentially no β-galactosidase was produced in developing BS167 cells even though the lacZ mRNA levels were the same as those in wild type cells. Also, no protein production was observed in strains lacking IfkA or IfkB eIF2α kinases. GFP fusions, with appropriate internal controls, were used to directly demonstrate that the bzpR 5' UTR, possessing 7 uORFs, suppressed translation by 12 fold. Suppression occurred even when all but one uORF was deleted, and translational suppression was removed when the ATG of the single uORF was mutated. CONCLUSIONS The findings indicate that BzpR regulates aspects of the development program in Dictyostelium, serving as a downstream effector of eIF2α phosphorylation. Its production is temporally and spatially regulated by eIF2α phosphorylation by IfkA and IfkB and through the use of uORFs within the bzpR 5' UTR.

The TET (ten-eleven translocation) family of α-ketoglutarate (α-KG)-dependent dioxygenases catalyzes the sequential oxidation of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine and 5-carboxylcytosine, leading to eventual DNA demethylation. The TET2 gene is a bona fide tumor suppressor frequently mutated in leukemia, and TET enzyme activity is inhibited in IDH1/2-mutated tumors by the oncometabolite 2-hydroxyglutarate, an antagonist of α-KG, linking 5mC oxidation to cancer development. We report here that the levels of 5hmC are dramatically reduced in human breast, liver, lung, pancreatic and prostate cancers when compared with the matched surrounding normal tissues. Associated with the 5hmC decrease is the substantial reduction of the expression of all three TET genes, revealing a possible mechanism for the reduced 5hmC in cancer cells. The decrease of 5hmC was also observed during tumor development in different genetically engineered mouse models. Together, our results identify 5hmC as a biomarker whose decrease is broadly and tightly associated with tumor development.Oncogene advance online publication, 5 March 2012; doi:10.1038/onc.2012.67.