Search tips
Search criteria

Results 1-14 (14)

Clipboard (0)

Select a Filter Below

more »
Year of Publication
1.  Proteolytic Activation of the Porcine Epidemic Diarrhea Coronavirus Spike Fusion Protein by Trypsin in Cell Culture 
Journal of Virology  2014;88(14):7952-7961.
Isolation of porcine epidemic diarrhea coronavirus (PEDV) from clinical material in cell culture requires supplementation of trypsin. This may relate to the confinement of PEDV natural infection to the protease-rich small intestine of pigs. Our study focused on the role of protease activity on infection by investigating the spike protein of a PEDV isolate (wtPEDV) using a reverse genetics system based on the trypsin-independent cell culture-adapted strain DR13 (caPEDV). We demonstrate that trypsin acts on the wtPEDV spike protein after receptor binding. We mapped the genetic determinant for trypsin-dependent cell entry to the N-terminal region of the fusion subunit of this class I fusion protein, revealing a conserved arginine just upstream of the putative fusion peptide as the potential cleavage site. Whereas coronaviruses are typically processed by endogenous proteases of the producer or target cell, PEDV S protein activation strictly required supplementation of a protease, enabling us to study mechanistic details of proteolytic processing.
IMPORTANCE Recurring PEDV epidemics constitute a serious animal health threat and an economic burden, particularly in Asia but, as of recently, also on the North-American subcontinent. Understanding the biology of PEDV is critical for combatting the infection. Here, we provide new insight into the protease-dependent cell entry of PEDV.
PMCID: PMC4097775  PMID: 24807723
2.  Transcription bypass of DNA lesions enhances cell survival but attenuates transcription coupled DNA repair 
Nucleic Acids Research  2014;42(21):13242-13253.
Transcription-coupled DNA repair (TCR) is a subpathway of nucleotide excision repair (NER) dedicated to rapid removal of DNA lesions in the transcribed strand of actively transcribed genes. The precise nature of the TCR signal and how the repair machinery gains access to lesions imbedded in stalled RNA polymerase II (RNAP II) complexes in eukaryotic cells are still enigmatic. RNAP II has an intrinsic capacity for transcription bypass of DNA lesions by incorporation or misincorporation of nucleotides across the lesions. It has been suggested that transcription bypass of lesions, which exposes the lesions, may be required for TCR. Here, we show that E1103G mutation of Rpb1, the largest subunit of RNAP II, which promotes transcription bypass of UV-induced cyclobutane pyrimidine dimers (CPDs), increases survival of UV irradiated yeast cells but attenuates TCR. The increased cell survival is independent of any NER subpathways. In contrast, G730D mutation of Rpb1, which impairs transcription bypass of CPDs, enhances TCR. Our results suggest that transcription bypass of lesions attenuates TCR but enhances cell tolerance to DNA lesions. Efficient stalling of RNAP II is essential for efficient TCR.
PMCID: PMC4245964  PMID: 25389266
3.  Clinical efficacy of radical nephrectomy versus nephron-sparing surgery on localized renal cell carcinoma 
The aim of the present study was to compare the clinical efficacy of radical nephrectomy (RN) with nephron-sparing surgery (NSS) in treating patients with localized renal cell carcinoma (RCC).
The literature search was performed in PubMed, MEDLINE Springer, Elsevier Science Direct, Cochrane Library, and Google Scholar up to December 2012. The software Review Manager 5.1 and the STATA software package v.11.0 were used for analyses. The odds ratios (ORs) and its 95% confidence interval (95% CI) were calculated for comparison. Subgroup analyses were performed based on the tumor size of RCC.
In total, 10 studies with 10,174 RCC patients (7,050 treated with RN and 3,124 treated with NSS) were selected. The pooled estimate (OR = 1.58, 95% CI = 1.15–2.15, P = 0.004) showed a significantly lower rate of cancer-specific deaths in the patients treated with NSS compared to RN. However, no statistically significant differences were found in the rate of tumor recurrence (OR = 0.84, 95% CI = 0.67–1.06, P = 0.14) and complications (OR = 0.91, 95% CI = 0.51–1.63, P = 0.74) between the patients treated with NSS and RN. In addition, all the subgroup analyses presented consistent results with the overall analyses.
NSS had no significantly different from RN in tumor recurrence and complications for localized RCC. However, the significantly lower rate of cancer-specific deaths supported the use of NSS not only for RCC with tumor size >4.0 cm but also for tumor sizes ≤4.0 cm compared with RN.
PMCID: PMC4226856  PMID: 25374003
Meta-analysis; Nephron-sparing surgery; Radical nephrectomy; Renal cell carcinoma
4.  Further Study of Multigranulation T-Fuzzy Rough Sets 
The Scientific World Journal  2014;2014:927014.
The optimistic multigranulation T-fuzzy rough set model was established based on multiple granulations under T-fuzzy approximation space by Xu et al., 2012. From the reference, a natural idea is to consider pessimistic multigranulation model in T-fuzzy approximation space. So, in this paper, the main objective is to make further studies according to Xu et al., 2012. The optimistic multigranulation T-fuzzy rough set model is improved deeply by investigating some further properties. And a complete multigranulation T-fuzzy rough set model is constituted by addressing the pessimistic multigranulation T-fuzzy rough set. The full important properties of multigranulation T-fuzzy lower and upper approximation operators are also presented. Moreover, relationships between multigranulation and classical T-fuzzy rough sets have been studied carefully. From the relationships, we can find that the T-fuzzy rough set model is a special instance of the two new types of models. In order to interpret and illustrate optimistic and pessimistic multigranulation T-fuzzy rough set models, a case is considered, which is helpful for applying these theories to practical issues.
PMCID: PMC4156983  PMID: 25215336
5.  Insights into how Spt5 functions in transcription elongation and repressing transcription coupled DNA repair 
Nucleic Acids Research  2014;42(11):7069-7083.
Spt5, a transcription elongation factor, and Rpb4, a subunit of RNA polymerase II (RNAP II) that forms a subcomplex with Rpb7, play important roles in transcription elongation and repression of transcription coupled DNA repair (TCR) in eukaryotic cells. How Spt5 physically interacts with RNAP II, and if and/or how Spt5 and Rpb4/7 coordinate to achieve the distinctive functions have been enigmatic. By site-specific incorporation of the unnatural amino acid p-benzoyl-L-phenylalanine, a photoreactive cross-linker, we mapped interactions between Spt5 and RNAP II in Saccharomyces cerevisiae. Through its KOW4-5 domains, Spt5 extensively interacts with Rpb4/7. Spt5 also interacts with Rpb1 and Rpb2, two largest subunits of RNAP II, at the clamp, protrusion and wall domains. These interactions may lock the clamp to the closed conformation and enclose the DNA being transcribed in the central cleft of RNAP II. Deletion of Spt5 KOW4-5 domains decreases transcription elongation and derepresses TCR. Our findings suggest that Spt5 is a key coordinator for holding the RNAP II complex in a closed conformation that is highly competent for transcription elongation but repressive to TCR.
PMCID: PMC4066765  PMID: 24813444
6.  Broad Activity against Porcine Bacterial Pathogens Displayed by Two Insect Antimicrobial Peptides Moricin and Cecropin B 
Molecules and Cells  2013;35(2):106-114.
In response to infection, insects produce a variety of antimicrobial peptides (AMPs) to kill the invading pathogens. To study their physicochemical properties and bioactivities for clinical and commercial use in the porcine industry, we chemically synthesized the mature peptides Bombyx mori moricin and Hyalophora cecropia cecropin B. In this paper, we described the antimicrobial activity of the two AMPs. Moricin exhibited antimicrobial activity on eight strains tested with minimal inhibitory concentration values (MICs) ranging between 8 and 128 μg/ml, while cecropin B mainly showed antimicrobial activity against the Gramnegative strains with MICs ranging from 0.5 to 16 μg/ml. Compared to the potent antimicrobial activity these two AMPs displayed against most of the bacterial pathogens tested, they exhibited limited hemolytic activity against porcine red blood cells. The activities of moricin and cecropin B against Haemophilus parasuis SH 0165 were studied in further detail. Transmission electron microscopy (TEM) of moricin and cecropin B treated H. parasuis SH 0165 indicated extensive damage to the membranes of the bacteria. Insights into the probable mechanism utilized by moricin and cecropin B to eliminate pathogens are also presented. The observations from this study are important for the future application of AMPs in the porcine industry.
PMCID: PMC3887904  PMID: 23456332
antimicrobial peptide; cecropin B; Haemophilus parasuis SH 0165; moricin; transmission electron microscopy
7.  Computed tomography-guided core needle biopsy of lung lesions: Diagnostic yield and correlation between factors and complications 
Oncology Letters  2013;7(1):288-294.
The aim of the present study was to determine the diagnostic accuracy of computed tomography (CT)-guided core needle biopsy (CNB) and to retrospectively analyze the correlation between the factors and complications of the procedure. Between January 2009 and June 2010, CNB was performed on 345 lung lesions in 343 patients. These patients were then followed up for at least two years. The sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of the CNB diagnoses were calculated. The correlation between factors, such as smoking, positoin and maximal diameter, and the complications of pneumothorax and hemorrhage was analyzed by χ2 test. The sensitivity, specificity, accuracy, PPV and NPV of the CNB diagnoses were 97.3, 100, 97.7, 100 and 87.7%, respectively. A statistically significant correlation was found between pneumothorax and the factors of smoking (P=0.015) and position (P<0.01) and length of the needle in the normal parenchyma (P=0.011), as well as between hemorrhage and the maximal diameter (P=0.005) and length of the needle in the normal parenchyma (P<0.01) and the frequency of needle adjustments (P<0.01). A CT-guided core needle biopsy of the lung lesions provides a high diagnostic yield. Smoking, the decubitus position and a longer length of the needle in the normal parenchyma were found to represent risk factors for a pneumothorax. In addition, a small diameter and longer length of the needle in the normal parenchyma and a more frequent adjustment of the needle were poor predictive factors of hemorrhage.
PMCID: PMC3861590  PMID: 24348866
CT-guided; core needle biopsy; pneumothorax; hemorrhage; core needle biopsy diagnosis; final diagnosis
8.  Transcription analysis of the porcine alveolar macrophage response to porcine circovirus type 2 
BMC Genomics  2013;14:353.
Porcine circovirus type 2 (PCV2) is the causal agent of postweaning multisystemic wasting syndrome (PMWS), which has severely impacted the swine industry worldwide. PCV2 triggers a weak and atypical innate immune response, but the key genes and mechanisms by which the virus interferes with host innate immunity have not yet been elucidated. In this study, genes that control the response of primary porcine alveolar macrophages (PAMs), the main target of PCV2, were profiled in vitro.
PAMs were successfully infected by PCV2-WH strain, as evidenced quantitative real-time polymerase chain reaction (qPCR) and immunofluorescence assay (IFA) results. Infection-related differential gene expression was investigated using pig microarrays from the US Pig Genome Coordination Program and validated by real-time PCR and enzyme-linked immunosorbent assay (ELISA). Microarray analysis at 24 and 48 hours post-infection (HPI) revealed 266 and 175 unique genes, respectively, that were differentially expressed (false discovery rate <0.05; fold-change >2). Only six genes were differentially expressed between 24 and 48 HPI. The up-regulated genes were principally related to immune response, cytokine activity, locomotion, regulation of cell proliferation, apoptosis, cell growth arrest, and antigen procession and presentation. The down-regulated genes were mainly involved in terpenoid biosynthesis, carbohydrate metabolism, translation, proteasome degradation, signal transducer activity, and ribosomal proteins, which were representative of the reduced vital activity of PCV2-infected cells.
PCV2 infection of PAMs causes up-regulation of genes related to inflammation, indicating that PCV2 may induce systematic inflammation. PCV2 persistently induced cytokines, mainly through the Toll-like receptor (TLR) 1 and TLR9 pathways, which may promote high levels of cytokine secretion. PCV2 may prevent apoptosis in PAMs by up-regulating SERPINB9 expression, possibly to lengthen the duration of PCV2 replication-permissive conditions. The observed gene expression profile may provide insights into the underlying immunological response and pathological changes that occur in pigs following PCV2 infection.
PMCID: PMC3680065  PMID: 23711280
9.  Efficacy of single dose of an inactivated porcine circovirus type 2 (PCV2) whole-virus vaccine with oil adjuvant in piglets 
Post-weaning multisystemic wasting syndrome (PMWS) associated with PCV2 is one of the most costly diseases currently faced by the swine industry. The development of effective vaccines against PCV2 infection has been accepted as an important strategy in the prophylaxis of PMWS.
In the present study, a PK-15 cell-adapted formalin-inactivated prototype vaccine candidate was prepared using a strain of PCV2 from China. Inactivation of the virus was accomplished using a standard formalin inactivation protocol. The protective properties of the inactivated PCV2 vaccine were evaluated in piglets. Ten 28-day-old pigs were randomly assigned to two groups, each with five. Group 1 was vaccinated intramuscularly with the inactivated virus preparation; Group 2 received sterile PBS as a placebo. By 28 days post-vaccination (DPV), Groups 1 and 2 were challenged intranasally and intramuscularly with 5 × 107 TCID50 of a virulent PCV2 isolate.
The vaccinated pigs seroconverted to PCV2 and had high levels of serum antibodies to PCV2 at 28 days after vaccination, whereas the control pigs remained seronegative. No significant signs of clinical disease were recorded following the challenge with PCV2, but moderate amounts of PCV2 antigen were detected in most lymphoid organs of the control pigs. PCV2 was detected in two out of the five vaccinated pigs. Furthermore, pathological lesions and viremia were milder in the vaccinated group.
The obtained results indicate that the inactivated PCV2 virus vaccine with an oil adjuvant induce an immunological response in pigs that appears to provide protection from infection with PCV2. The vaccine, therefore, may have the potential to serve as a vaccine aimed to protect pigs from developing PMWS.
PMCID: PMC3539982  PMID: 23171757
Porcine circovirus type 2; Post-weaning multisystemic wasting syndrome; Single-dose immunization; Formalin-inactivated vaccine
10.  Design and Synthesis of Benzenesulfonamide Derivatives as Potent Anti-Influenza Hemagglutinin Inhibitors 
ACS Medicinal Chemistry Letters  2011;2(8):603-607.
Structural optimization of salicylamide-based hemagglutinin (HA) inhibitor 1 resulted in the identification of cis-3-(5-hydroxy-1,3,3-trimethylcyclohexylmethylamino)benzenesulfonamide 28 and its derivatives as potent anti-influenza agents. The lead compound 28 and its 2-chloro analogue 40 can effectively prevent cytopathic effects (CPE) caused by infection of influenza A/Weiss/43 strain (H1N1) with EC50 values of 210 and 86 nM, respectively. Mechanism of action studies indicate that 40 and its analogues inhibit the virus fusion with host endosome membrane by binding to HA and stabilizing the prefusion HA structure. With significantly improved metabolic stability, the reported series represents the first generation of orally bioavailable HA inhibitors that have a good selectivity window and potential for further development as novel anti-influenza agents.
PMCID: PMC4018120  PMID: 24900355
Anti-influenza; hemagglutinin; benzenesulfonamide; inhibitor
11.  New Variants of Porcine Epidemic Diarrhea Virus, China, 2011 
Emerging Infectious Diseases  2012;18(8):1350-1353.
In 2011, porcine epidemic diarrhea virus (PEDV) infection rates rose substantially in vaccinated swine herds. To determine the distribution profile of PEDV outbreak strains, we sequenced the full-length spike gene from samples from 9 farms where animals exhibited severe diarrhea and mortality rates were high. Three new PEDV variants were identified.
PMCID: PMC3414035  PMID: 22840964
porcine epidemic diarrhea virus; prevalence; China; phylogeny; variant strain; viruses
12.  Combination of CT-guided hookwire localization and video-assisted thoracoscopic surgery for pulmonary nodular lesions: Analysis of 103 patients 
Oncology Letters  2012;4(4):824-828.
At present, there is no standardized method for the diagnosis and management of pulmonary nodular lesions (PNLs) smaller than 3 cm. This study investigated the use of computed tomography (CT)-guided hookwire localization and video-assisted thoracoscopic surgery (VATS) for PNLs. A total of 103 patients undergoing CT-guided hook-wire localization and VATS were enrolled, and 107 lesions were collected. We assessed the localization achievement ratio, complications rate, conversion thoracotomy rate, intraoperative dislodgement rate, pathological diagnosis rate, duration of surgery and average days of hospitalization. All 107 nodules from 103 patients were successfully localized (100%), the asymptomatic pneumothorax rate was 36.9%, the asymptomatic hemorrhage rate was 40.8% and the simultaneous pneumothorax and hemorrhage rate was 8.7%. A conversion thoracotomy was required in 2 (1.9%) patients and the intraoperative dislodgement rate was 2.9%. The average time for localization was 11±4 min, and the average times for wedge resection and lobectomies were 16±2 and 95±30 min, respectively. The mean hospitalization time following the surgery was 6±3 days. All 107 nodules managed to achieve pathological diagnoses. A combination of CT-guided hook-wire localization and VATS for PNL is a safe and efficient procedure of great clinical value.
PMCID: PMC3506590  PMID: 23205107
pulmonary nodular lesions; ground-glass nodules; hookwire system; video-assisted thoracoscopic surgery
13.  Transcription analysis on response of porcine alveolar macrophages to Haemophilus parasuis 
BMC Genomics  2012;13:68.
Haemophilus parasuis (H. parasuis) is the etiological agent of Glässer's disease in pigs. Currently, the molecular basis of this infection is largely unknown. The innate immune response is the first line of defense against the infectious disease. Systematical analysis on host innate immune response to the infection is important for understanding the pathogenesis of the infectious microorganisms.
A total of 428 differentially expressed (DE) genes were identified in the porcine alveolar macrophages (PAMs) 6 days after H. parasuis infection. These genes were principally related to inflammatory response, immune response, microtubule polymerization, regulation of transcript and signal transduction. Through the pathway analysis, the significant pathways mainly concerned with cell adhesion molecules, cytokine-cytokine receptor interaction, complement and coagulation cascades, toll-like receptor signaling pathway, MAPK signaling pathway, suggesting that the host took different strategies to activate immune and inflammatory response upon H. parasuis infection. The global interactions network and two subnetworks of the proteins encoded by DE genes were analyzed by using STRING. Further immunostimulation analysis indicated that mRNA levels of S100 calcium-binding protein A4 (S100A4) and S100 calcium-binding protein A6 (S100A6) in porcine PK-15 cells increased within 48 h and were sustained after administration of lipopolysaccharide (LPS) and Poly (I:C) respectively. The s100a4 and s100a6 genes were found to be up-regulated significantly in lungs, spleen and lymph nodes in H. parasuis infected pigs. We firstly cloned and sequenced the porcine coronin1a gene. Phylogenetic analysis showed that poCORONIN 1A belonged to the group containing the Bos taurus sequence. Structural analysis indicated that the poCORONIN 1A contained putative domains of Trp-Asp (WD) repeats signature, Trp-Asp (WD) repeats profile and Trp-Asp (WD) repeats circular profile at the N-terminus.
Our present study is the first one focusing on the response of porcine alveolar macrophages to H. parasuis. Our data demonstrate a series of genes are activated upon H. parasuis infection. The observed gene expression profile could help screening the potential host agents for reducing the prevalence of H. parasuis and further understanding the molecular pathogenesis associated with H. parasuis infection in pigs.
PMCID: PMC3296652  PMID: 22330747
14.  Use of a radiopaque localizer grid to reduce radiation exposure 
Minimally invasive spine surgery requires placement of the skin incision at an ideal location in the patient's back by the surgeon. However, numerous fluoroscopic x-ray images are sometimes required to find the site of entry, thereby exposing patients and Operating Room personnel to additional radiation. To minimize this exposure, a radiopaque localizer grid was devised to increase planning efficiency and reduce radiation exposure.
The radiopaque localizer grid was utilized to plan the point of entry for minimally invasive spine surgery. Use of the grid allowed the surgeon to accurately pinpoint the ideal entry point for the procedure with just one or two fluoroscopic X-ray images.
The reusable localizer grid is a simple and practical device that may be utilized to more efficiently plan an entry site on the skin, thus reducing radiation exposure. This device or a modified version may be utilized for any procedure involving the spine.
PMCID: PMC3177900  PMID: 21827694
Radiation; Exposure; Minimally Invasive; Spine Surgery; Localization; Innovation; Grid

Results 1-14 (14)