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  • Author: Qing Sun x
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Virulence factors and antibiotic resistance of avian pathogenic Escherichia coli in eastern China

Abstract

Introduction

Avian pathogenicEscherichia coli (APEC) causes serious colibacillosis and significant economic losses. Data on profiles of virulence factors and antibiotic resistances among APEC strains are crucial to the control of infection. In this study, strains were isolated from eastern China, and the prevalence of virulence factors and distribution of antibiotic resistance were determined.

Material and Methods

APEC strains were isolated and characterised by PCR for O serogroups, virulence factor genes, antibiotic resistance, and phylogenetic groups.

Results

O78 was the most prevalent serogroup and type A was the most frequent phylogenetic group. ThefimH,feoB, andiron genes were the most prevalent among the isolates. All isolates were multiresistant, and all strains were resistant to ampicillin and tetracycline, which are widely used in the poultry industry in China.

Conclusion

This study provided important data on the presence of virulence genes and antibiotic resistance profiles of APEC from poultry farms in eastern China.

Open access
Pressure dependence of the band gap energy for the dilute nitride GaNxAs1−x

Abstract

A model is developed to describe the pressure dependence of the band gap energy for the dilute nitride GaNxAs1–x. It is found that the sublinear pressure dependence of E is due to the coupling interaction between E+ and E. We have also found that GaNxAs1−x needs much larger pressure than GaAs to realize the transition from direct to indirect band gap. It is due to two factors. One is the coupling interaction between the E+ and E. The other is that the energy difference between the X conduction band minimum (CBM) and the G CBM in GaNxAs1−x is larger than that in GaAs. In addition, we explain the phenomenon that the energy difference between the X CBM and the G CBM in GaNxAs1−x is larger than that in GaAs. It is due to the impurity-host interaction.

Open access
The Diagnostic Value of Brain Magnetic Resonance Imaging in Detecting CNS Diseases Among Advanced AIDS Patients

Abstract

Objective To investigate the diagnostic value of brain magnetic resonance imaging in detecting central nervous system diseases among AIDS patients of different levels of T cells.

Methods Total of 164 AIDS patients who did not receive antiviral treatment were divided into 2 groups according to their baseline CD4+ T cell counts. Group A had CD4+ T cell below or equal to 50 cells/μl (n = 81) and group B had CD4+ T cells over 50 cells/μl (n = 83). All patients underwent brain MRI scan. Imaging analysis and the prevalence of the central nervous system disorders were compared between two groups.

Results Among them 48 cases were found of abnormal brain MRI, group A was higher than group B (35.8% vs. 22.9%) although without statistical significance (P = 0.065). Altogether 48 cases were diagnosed as AIDS related central nervous system disorders based on clinical symptoms, signs and laboratory findings. The prevalence of CNS disorders was higher in group A than in group B (41.9% vs. 16.8%) with statistical significance (P < 0.01).

Conclusions The patients with CD4+ T cell count less than or equal to 50 cells/μl had high prevalence of CNS diseases. Brain MRI plays an important role in the diagnosis and differentiation of CNS diseases in advanced AIDS patients. This study suggests patients with low CD4+ T cell count (≤ 50/μl) should routinely undergo MRI examination.

Open access
Phylogenetic analysis of VP1 region of CA16 isolated from children with severe hand-foot-mouth disease

Abstract

Background: CA16 and enterovirus 71 are two key etiological agents for children’s hand-foot-mouth disease (HFMD). Large-scale HFMD outbreaks have taken place every year in Liaocheng City, Shandong Province of China since 2008.

Objective: We investigated the genetic background and phyletic evolution of coxsackie virus A16 (CA16)-related severe HFMD in children from Liaocheng City.

Method: CA16 was screened from throat swab and anus specimens obtained from children with severe HFMD between 2008 and 2010. Specific primers were used to amplify the VP1 region of CA 16 for sequence analysis.

Result: A total of 461 specimens were detected to be enterovirus positive from 2008 to 2010 and 401 specimens were CA16 positive. The nucleotide and amino acid sequences of 16 isolates from children with severe HFMD were compared with the reference sequences, and the nucleotide homology was 91.43%-98.65%, and the amino acid homology was 97.98%-100%. Of the16 isolates, 9 isolates and BJ03-ZDP (AY821798), Shzh00-1 (AY790926), Shzh05-1 (EU262658), and GZ08 (FJ198212) strains isolated from Chinese mainland were located on the same branch; the remaining 7 isolates, the strains isolated from Malaysia, Thailand, Vietnam, Australia and other neighboring countries. AF177911 from Taiwan andshzh01-69 strain (AY895111) from Shenzhen were located on another branch.

Conclusion: CA16 is one of the major pathogens of HFMD and the homology of strains is high.

Open access
A study on blocking store-operated Ca2+ entry in pulmonary arterial smooth muscle cells with xyloketals from marine fungi

Abstract

In this study, the effect of four xyloketals 1-4 on store-operated calcium entry (SOCE) was investigated in primary distal pulmonary arterial smooth muscle cells (PASMCs) isolated from mice. The results showed that xyloketal A (1), an unusual ketal with C-3 symmetry, exhibited strong SOCE blocking activity. Secretion of interleukin-8 (IL-8) was also inhibited by xyloketal A. The parallel artificial membrane permeability assay (PAMPA) of 1-4 suggested that these xyloketals penetrated easily through the cell membrane. Moreover, the molecular docking study of xyloketal A with activation region of the stromal interaction molecule (STIM) 1 and the calcium release-activated calcium modulator (ORAI) 1 (STIM1-ORAI1) protein complex, the key domain of SOCE, revealed that xyloketal A exhibited a noncovalent interaction with the key residue lysine 363 (LYS363) in the identified cytosolic regions in STIM1-C. These findings provided useful information about xyloketal A as a SOCE inhibitor for further evaluation.

Open access
Effect of Stubble Heights and Treatment Duration Time on the Performance of Water Dropwort Floating Treatment Wetlands (FTWS)

Effect of Stubble Heights and Treatment Duration Time on the Performance of Water Dropwort Floating Treatment Wetlands (FTWS)

Floating treatment wetlands (FTWs) with Water Dropwort (Oenanthe javanica) were established in winter to investigate their potential role in the purification of eutrophicated water, and to identify the effects of different stubble heights of the Water Dropwort on the performance of the FTWs. The results of the experiments demonstrated: The Water Dropwort FTWs were effective in buffering the pH of the experimental water. The Water Dropwort FTWs were efficient in purifying eutrophicated water, with removal rate for total nitrogen (TN), total phosphorus (TP), ammonium nitrogen (NH4 + - N), and nitrate nitrogen (NO3 - - N) at 91.3, 58.0, 94.6, and 95.5% in the 15-day experiment, respectively. No significant difference in the purification effect was found among different stubble heights of Water Dropwort FTWs. Significant differences between the zero control and the FTWs were found for the removal of TP in the first 11 days; and for the removal of NH4 + - N in the first 4 days. No significant difference was found between the zero control and the FTWs for NO3 - - N in the first 4 days, but significant difference was detected after day 4. The optimum treatment duration time for the FTWs with Water Dropwort will depend on the nutrients to be removed. These results will provide basis for further application of the FTWs at large scale, as well as for future studies on the mechanism of nutrient removal process.

Open access