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Articles by Jian Zhou
Total Records ( 7 ) for Jian Zhou
  J. Wang , Y.-H. Li , M.-H. Li , J.-G. Zhao , Y.-Q. Bao and Jian Zhou
  Aims  To quantify the capillary permeability of the lower extremity muscles using dynamic contrast-enhanced magnetic resonance imaging in healthy control subjects without diabetes and patients with diabetes before and after percutaneous angioplasty.

Methods  Fifty-five patients (30 without diabetes, 25 with Type 2 diabetes with occluded vasculature of the lower extremities) were examined by dynamic contrast-enhanced magnetic resonance imaging. The transfer constant (K-trans) of the tibialis anterior muscle was determined before (for all patients) and after (for patients with diabetes only) percutaneous angioplasty of the intrapopliteal artery. Clinical assessment was also recorded. Statistical significant differences were defined at the level of P < 0.05.

Results  Before percutaneous angioplasty, patients with diabetes displayed significantly lower K-trans values in the tibialis anterior muscles than control subjects. Although percutaneous angioplasty increased the K-trans of these patients, the final values were still less than those of the control group. Differences were also observed between the groups in the Fontaine classification and ankle-brachial index, which reflect ischaemia in the lower extremities. After percutaneous angioplasty, these values were increased in the group with diabetes.

Conclusion  K-trans can be used to quantify changes in the capillary permeability of the lower extremity muscles, reflecting the microcirculation of the lower extremities.

  Jian Zhou , Huabin Wang , Xianyong Fang , Liang Tao and Li Zhao
  A whisper intelligibility enhancement method was proposed based on the Real-valued Discrete Gabor Transform (RDGT) in the joint time frequency domain where the RDGT can change the density of the spectrum through the over sample rate parameter. An optimal logarithmic spectrum estimator was derived based on RDGT coefficients. Experimental results showed that the proposed method improved the intelligibility of enhanced whisper in an adverse noise environment when using a proper over sample rate value. The largest gains in intelligibility were got when the over sample rate value is set to 16 or 32. The proposed method outperforms other four speech enhancement algorithms in terms of intelligibility improvement. The experimental results also implied that the intelligibility performance of the conventional speech enhancement algorithms might be improved when increasing the density of the time-frequency spectrum properly.
  Qiuhe Lu , Jing Han , Ligang Zhou , Jian Zhou and Hua Xiang
  The haloarchaeon Haloferax mediterranei has shown promise for the economical production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), a desirable bioplastic. However, little is known at present about the genes involved in PHBV synthesis in the domain Archaea. In this study, we cloned the gene cluster (phaECHme) encoding a polyhydroxyalkanoate (PHA) synthase in H. mediterranei CGMCC 1.2087 via thermal asymmetric interlaced PCR. Western blotting revealed that the phaEHme and phaCHme genes were constitutively expressed, and both the PhaEHme and PhaCHme proteins were strongly bound to the PHBV granules. Interestingly, CGMCC 1.2087 could synthesize PHBV in either nutrient-limited medium (supplemented with 1% starch) or nutrient-rich medium, up to 24 or 18% (wt/wt) in shaking flasks. Knockout of the phaECHme genes in CGMCC 1.2087 led to a complete loss of PHBV synthesis, and only complementation with the phaECHme genes together (but not either one alone) could restore to this mutant the capability for PHBV accumulation. The known haloarchaeal PhaC subunits are much longer at their C termini than their bacterial counterparts, and the C-terminal extension of PhaCHme was proven to be indispensable for its function in vivo. Moreover, the mixture of purified PhaEHme/PhaCHme (1:1) showed significant activity of PHA synthase in vitro. Taken together, our results indicated that a novel member of the class III PHA synthases, composed of PhaCHme and PhaEHme, accounted for the PHBV synthesis in H. mediterranei.
  Ligang Zhou , Meixian Zhou , Chaomin Sun , Jing Han , Qiuhe Lu , Jian Zhou and Hua Xiang
  The precise nick site in the double-strand origin (DSO) of pZMX201, a 1,668-bp rolling-circle replication (RCR) plasmid from the haloarchaeon Natrinema sp. CX2021, was determined by electron microscopy and DSO mapping. In this plasmid, DSO nicking occurred between residues C404 and G405 within a heptanucleotide sequence (TCTC/GGC) located in the stem region of an imperfect hairpin structure. This nick site sequence was conserved among the haloarchaeal RCR plasmids, including pNB101, suggesting that the DSO nick site might be the same for all members of this plasmid family. Interestingly, the DSOs of pZMX201 and pNB101 were found to be cross-recognized in RCR initiation and termination in a hybrid plasmid system. Mutation analysis of the DSO from pZMX201 (DSOZ) in this hybrid plasmid system revealed that: (i) the nucleotides in the middle of the conserved TCTCGGC sequence play more-important roles in the initiation and termination process; (ii) the left half of the hairpin structure is required for initiation but not for termination; and (iii) a 36-bp sequence containing TCTCGGC and the downstream sequence is essential and sufficient for termination. In conclusion, these haloarchaeal plasmids, with novel features that are different from the characteristics of both single-stranded DNA phages and bacterial RCR plasmids, might serve as a good model for studying the evolution of RCR replicons.
  Jian Zhou and Gary W. Blissard
  The Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) GP64 envelope glycoprotein is essential for virus entry and plays an important role in virion budding. An AcMNPV construct that contains a deletion of the gp64 gene is unable to propagate infection from cell to cell, and this defect results from both a severe reduction in the production of budded virions and the absence of GP64 on virions. In the current study, we examined GP64 proteins containing N- and C-terminal truncations of the ectodomain and identified a minimal construct capable of targeting the truncated GP64 to budded virions. The minimal budding and targeting construct of GP64 contained 38 amino acids from the mature N terminus of the GP64 ectodomain and 52 amino acids from the C terminus of GP64. Because the vesicular stomatitis virus (VSV) G protein was previously found to rescue infectivity of a gp64null AcMNPV, we also examined a small C-terminal construct of the VSV G protein. We found that a construct containing 91 amino acids from the C terminus of VSV G (termed G-stem) was capable of rescuing AcMNPV gp64null virion budding to wild-type (wt) or nearly wt levels. We also examined the display of chimeric proteins on the gp64null AcMNPV virion. By generating viruses that expressed chimeric influenza virus hemagglutinin (HA) proteins containing the GP64 targeting domain and coinfecting those viruses with a virus expressing the G-stem construct, we demonstrated enhanced display of the HA protein on gp64null AcMNPV budded virions. The combined use of gp64null virions, VSV G-stem-enhanced budding, and GP64 domains for targeting heterologous proteins to virions should be valuable for biotechnological applications ranging from targeted transduction of mammalian cells to vaccine production.
  Jian Zhou and Gary W. Blissard
  Enveloped virus entry into host cells is typically initiated by an interaction between a viral envelope glycoprotein and a host cell receptor. For budded virions of the baculovirus Autographa californica multicapsid nucleopolyhedrovirus, the envelope glycoprotein GP64 is involved in host cell receptor binding, and GP64 is sufficient to mediate low-pH-triggered membrane fusion. To better define the role of GP64 in receptor binding, we generated and characterized a panel of antisera against subdomains of GP64. Eight subdomain-specific antisera were generated, and their reactivities with GP64 proteins and neutralization of virus infectivity and binding were examined. Antibodies directed against the N-terminal region of GP64 (amino acids 21 to 159) showed strong neutralization of infectivity and effectively inhibited binding of 35S-labeled budded virions to Sf9 cells. In addition, we generated virions displaying truncated GP64 constructs. A construct displaying the N-terminal 274 amino acids (residues 21 to 294) of the ectodomain was sufficient to mediate virion binding. Additional studies of antisera directed against small subdomains revealed that an antiserum against a 40-amino-acid region (residues 121 to 160) neutralized virus infectivity. Site-directed mutagenesis was subsequently used for functional analysis of that region. Recombinant viruses expressing GP64 proteins with single amino acid substitutions within amino acids 120 to 124 and 142 to 148 replicated to high titers, suggesting that those amino acids were not critical for receptor binding or other important GP64 functions. In contrast, GP64 proteins with single amino acid substitutions of residues 153 and 156 were unable to substitute for wild-type GP64 and did not rescue a gp64 knockout virus. Further analysis showed that these substitutions substantially reduced binding of recombinant virus to Sf9 cells. Thus, the amino acid region from positions 21 to 159 was identified as a putative receptor binding domain, and amino acids 153 and 156 appear to be important for receptor binding.
  Marcos Pita , Jian Zhou , Kalayil Manian Manesh , Jan Halamek , Evgeny Katz and Joseph Wang
  We describe preliminary results on an enzyme logic sensing system for a reliable assessment of the overall physiological condition during an injury. The new system consists of AND and XOR logic gates based on the concerted operation of tyrosinase, glucose oxidase, lactate dehydrogenase and microperoxidase-11. The enzyme logic system is activated by physiologically relevant concentrations of the input signals of biomarkers: norepinephrine, oxygen, glucose and lactate mimicking in vitro different injuries, including trauma brain injury and hemorrhagic shock. We anticipate that such biochemical logic gates will eventually facilitate decision-making towards the initiation of an optimal timely therapeutic intervention, leading to improved survival of injured soldiers and civilians. The biochemical logic system analyzing biomarker signals represents the first step towards digitally operating sensors and actuators with chemical information processing steps.
 
 
 
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