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Articles by S Yu
Total Records ( 5 ) for S Yu
  S Yu , B Zheng , X Zhao and Y. Feng

A bioinformatic screening of the genome of the thermophilic bacterium Fervidobacterium nodosum Rt17-B1 for ester-hydrolyzing enzymes revealed a putative bacterial esterase (FNE) encoded by Fond_1301 with typical GDSL family motifs. To confirm its putative esterase function, the FNE gene was cloned, functionally expressed in Escherichia coli, and purified to homogeneity. Recombinant FNE exhibited the highest esterase activity of 14,000 U/mg with p-nitrophenyl acetate (pNPC2) as substrate. The catalytic efficiency (kcat/Km) toward p-nitrophenyl acetate (C2) was approximately 120-fold higher than toward p-nitrophenyl butyrate (C4). No significant esterase activity was observed for the substrates with a chain length ≥C8. The monomeric enzyme has a molecular mass of 27.5 kDa and exhibits optimal activity around 75°C, at pH 8.5. Its thermostability is relatively high with a half-life of 80 min at 70°C, but less stable compared with some other hyperthermophilic esterases. A structural model was constructed using acetylesterase from Aspergillus aculeatus as a template. The structure showed an /β-hydrolase fold and indicated the presence of a typical catalytic triad consisting of a serine, aspartate, and histidine, which was verified by site-directed mutagenesis. Sequence analysis showed that FNE was only distantly related to other esterases. A comparison of the conserved motifs shared with GDSL proteins revealed that FNE could be grouped into GDSL family and was further classified as SGNH hydrolase.

  H Chen , W Wang , C Song , S Yu and C. Ding

Currently available vaccines against Mycobacterium bovis, the causative agent of tuberculosis, do not provide reliable efficacy and there is therefore a need for a novel vaccine with improved efficacy. Here, we use protein transduction technology to deliver DNA vaccines expressing mycobacterial antigens directly to target cells. We used various protein transduction domain (PTD) proteins including the VP22 conjugate from Marek's disease virus serotype 1 (MDV-1), as delivery systems for DNA constructs encoding the antigens early secretory antigenic target-6 kDa (ESAT-6) protein and culture filtrate protein 10 (CFP-10) of M. bovis. The eukaryotic expression plasmid pZ106, encoding antigens ESAT-6 and CFP-10, conjugated to various PTDs, was used to construct experimental preparations. Our findings demonstrated that VP22 alone or in combination with CFP-10:ESAT-6 fusion protein could spread into all the nuclei of the cell monolayer surrounding the transfected cells. Whereas trans-activating transcriptional PTD showed limited delivery of the fusion protein and 8R peptide was unable to deliver the fusion protein into any untransfected cells. We have demonstrated that immunization with a preparation fused to VP22 leads to a higher antibody and interferon- titer (P < 0.05). Taken together, our results demonstrated that MDV-1 VP22 serves as a potential immune enhancer in gene therapy and immunization using DNA vaccines, offering a novel approach for the prevention of M. bovis infection.

  L Mazzone , S Yu , C Blair , B. C Gunter , Z Wang , R Marsh and B. S. Peterson

The authors sought to study activity in neural circuits that subserve the inhibition of a semi-involuntary motor behavior, eye blinking, in children and adults with Tourette syndrome and in healthy comparison subjects.


Functional magnetic resonance imaging was used to scan 120 participants (51 with Tourette syndrome and 69 comparison subjects) as they either blinked normally or successfully inhibited eye blinking. The authors compared the blood-oxygen-level dependent signal during these two conditions across the Tou­rette and comparison groups.


Results: Relative to comparison subjects, patients with Tourette syndrome activated more strongly the frontal cortex and striatum during eye blink inhibition. Activation increased more with age in the dorsolateral and inferolateral prefrontal cortex and caudate nucleus in the Tourette group relative to comparison subjects. In addition, the Tourette group more strongly activated the middle frontal gyrus, dorsal anterior cingulate, and temporal cortices. The severity of tic symptoms in the Tourette group correlated inversely with activation in the putamen and inferolateral prefrontal cortex.


Conclusions: Frontostriatal activity is increased in persons with Tourette syndrome during the inhibition of eye blinks. Activation of frontostriatal circuits in this population may help to maintain regulatory control over semi-involuntary behaviors, whether these are tics or eye blinks.

  K. B Dorsey , M Mauldon , R Magraw , J Valka , S Yu and H. M. Krumholz

To describe pediatric clinicians’ adherence to practice recommendations for obesity prevention and treatment, we conducted a cross-sectional analysis of 227 medical records of 3- to 18-year-old patients (seen from September 2003 to April 2004) and a longitudinal analysis of data from 632 overweight and obese patients (followed through March 2006). The cross-sectional analysis showed that early practice adopters (n = 3) more frequently recorded BMI (91% of patients), a diagnosis (89%), and counseling (82%) compared with late adopters (n = 9; 34%, 51%, and 48% of patients, respectively; P < .001). The longitudinal analysis showed that among overweight and obese patients, documentation of BMI dropped from 96% at the first clinic visit to 27% by the fifth visit; documentation of individual risk behaviors fell from ≥72% at the first visit to ≤23% at the fifth visit. Despite initial adoption of screening and assessment practices, clinicians’ attention to weight management diminished over time.

  Z Zhao , B Ciric , S Yu , G. X Zhang and A. Rostami

Loss of expression of the 3G11 epitope, present on disialoceramide that is predominantly found on CD4+ T cells, has been associated with a regulatory T cell (Treg) phenotype and tolerance induction in experimental autoimmune encephalomyelitis (EAE). Here we report that treatment with anti-3G11 mAb shifts the immune response from pro-inflammatory to tolerogenic and suppresses both chronic-progressive and relapsing–remitting EAE. This therapeutic effect can be achieved at different stages of EAE. Treatment with anti-3G11 mAb increased the proportion of Foxp3+CD25+CD4+ Tregs and IL-10 production while inhibiting production of pro-inflammatory cytokines and responsiveness to IL-2 and decreasing the proportion of Th17 cells. The effect of anti-3G11 mAb was diminished in IL-10–/– mice, indicating that this cytokine mediates some of its effects. As 3G11 belongs to the ganglioside family, which is expressed on the surface of both murine and human CD4+ T cells, targeting this class of molecules may provide a novel approach for treating autoimmune diseases.

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