Analysis of the Results of MP-Ab-IgM Detection of Serum,Bronchial Lavage Fluid,Pleural Effusion and Cerebrospinal Fluid in Children Suspected of Mycoplasma Pneumoniae Infection / 现代检验医学杂志

Objective To study the infection of MP-Ab IgM (MP) in serum,bronchial lavage fluid,pleural effusion and cere brospinal from pediatric patients with Mycoplasma Pneumoniae Pneumonia (MPP).Methods From March to June 2013,278 cases of patients suspected MP infection in Children's Hospital Affiliated to Capital Medical University were selected and the MP-Ab IgM of thcire serum,bronchial lavage fluid,pleural effusion and ccrebrospinal fluid specimens were detected with the method of particle agglutination test.Results 181 cases (104 cases of boys,77 cases of girls) of different specimens in (MP) were positive.All the serum samples,278 cases were detected positive serum specimen of 170 cases,the overall detection rate was 61.2％ (170/278),144 cases of bronchial lavage fluid was investigated at the same time,check out the posi rive 62 cases,and the detection rate was 43.1％ (62/144).19 cases for pleural effusion samples at the same time,checked out the positive 13 cases,and detection rate was 68.4％ (13/19).15 cases of cerebrospinal fluid specimens was investigated at the same time,checked out the positive in 1 case,and the detection rate was 6.7％ (1/ 15).Positive rate between different age groups was respectively:6 months～1 year group 29.0％ (9/31),～3 year group 51.0％ (25/49),～5 year group 56.1％ (23/41),～16 year group 79.0％ (124/157),6 months～1 year witb other age groups was statistically significant difference (P＜0.05).In 0.5～1 year,～3 year,～5 year,16 year～four age groups,different types of MP-Ab IgM positive specimens of the same patients,the corresponding results for A:serum type (111 cases) 7,21,13,70.B:serum and bronchoalveolar lavage fluid type (45 cases) 0,2,5,38.C:Serum pleural effusion (7 cases) 0,1,2,4.D:serum and cerebrospinal fluid (1 cases) 0,0,0,1;E:serum and bronchoalveolar lavage fluid and pleural effusion type (6 cases):0,0,2,4.F:bronchoalveolar lavage fluid type (11) 2,1,1,7.Conclusion MP infection varied,have atrend of younger age,and has a tendency to increase year by year,and the patient's infection rates have different characteristics.Positive serum of different age groups was gradually increased with age,infants and young children positive detection rate increased significantlychildren with severe multiple in older children.

The Biologic Characteristics of a Strain of Cellulosimicrobium cellulans and Its Utilization of Several Kinds of Benzoic Compounds / 微生物学通报

A strain of Cellulosimicrobium cellulans Ha8 was studied on its morphological, biological characteristics and its utilization of several kinds of benzoic compounds, the results showed this strain was Gram-positive, the long rod-shaped cells were changed into short rod-shape gradually. pH value from pH 6.0 to pH 9.0 and the temperature from 20 ℃ to 40 ℃ were good for its growth. It could not only hydrolyze protein and starch, use cellulose and pectin, decomposite chitin, liquify gelatin and fix nitrogen, but also use phenol, xylene, benzoic, cinnamic acids and diphenlamine as the sole carbon resource for its growth. It could tolerate 0 mmol/L~30 mmol/L, 0 mmol/L~8 mmol/L, 0 mmol/L~30 mmol/L, 0 mmol/L~15 mmol/L and 0 mmol/L ~ 40 mmol/L of benzoic acids, phenol, xylene, cinnamic acids and diphenlamine seperately, but could not use 2,4-dinitrophenol, o-Nitrophenol, 2-Methoxyphenol, aminobenzenesulfonic acid, catechol and o-Phenanthroline as its sole carbon resource.

Secreted expression and purification of dengue 2 virus full-length nonstructural glycoprotein NS1 in Pichia pastoris.

The dengue 2 virus (DEN-2) RNA (NGC strain) was used as a substrate to produce DNA clones of the full-length NS1 genes via reverse transcriptase synthesis of cDNA followed by polymerase chain reaction amplification of the NS1 region. Products were cloned into pPICZalphaB vector for sequencing and into Pichia pastoris for expression. A recombinant protein with a molecular size of approximately 80 KDa was secreted into the supernatant from the yeast cells when induced with methanol. The expressed protein was able to bind with mouse polyclonal antibody or NS1-specific monoclonal antibody of dengue 2 virus. Purified NS1-poly(His)-tagged fusion protein was obtained from the expressed product by passing through a metal-chelating affinity chromatographic (MCAC) column. The study also verified that our purified rNS1 protein retained its antigenicity. High-level production of the rNS1 protein up to 70 mg/l indicates that P. pastoris is an efficient expression system for dengue virus full-length NS1 glycoprotein.

[Analysis of ERG11 gene mutation in Candida albicans].

OBJECTIVE: To study the relationship between fluconazole (FCZ)-resistance of Candida albicans and the mutation of ERG11 gene encoding FCZ-targeted enzyme. METHOD: Three strains of FCZ-susceptible and 10 FCZ-resistent C. albicans were isolated from the urethra, vagina, oropharynx, respiratory tract, prostate secretion and blood samples. ERG11 gene was amplified by PCR using C.albicans genomic DNA extracts as the templates and the DNA sequences of the PCR products were determined and compared using BLAST and Clustal-W softwares. RESULTS: The comparison of ERG11 gene sequences identified mutations at 21 sites in 13 strains, including 17 same-sense and 4 missense mutations. Base substitutions at the sites of 348 bp and 383 bp resulting in D116E and K128T conversion may take place in both drug-resistant and drug-susceptible strains. The point mutation at the site of 1309 bp of FCZ-resistant strain may cause V437I change, and the base inversion at 1320 bp may give rise to A/C heterozygosity mutant of ERG11 gene, probably resulting in N440K conversion. CONCLUSION: FCZ-resistance of C. albicans may be associated with point mutations of V437I and N440K in ERG11 gene, but not with the point mutations of D166E and K128T.

Application of oligonucleotide array technology for the rapid detection of pathogenic bacteria of foodborne infections.

A rapid and accurate method for detection for common pathogenic bacteria in foodborne infections was established by using oligonucleotide array technology. Nylon membrane was used as the array support. A mutation region of the 23S rRNA gene was selected as the discrimination target from 14 species (genera) of bacteria causing foodborne infections and two unrelated bacterial species. A pair of universal primers was designed for PCR amplification of the 23S rRNA gene. Twenty-one species (genera)-specific oligonucleotide detection probes were synthesized and spotted onto the nylon membranes. The 23S rRNA gene amplification products of 14 species of pathogenic bacteria were hybridized to the oligonucleotide array. Hybridization results were analyzed with digoxigenin-linked enzyme reaction. Results indicated that nine species of pathogenic bacteria (Escherichia coli, Campylobacter jejuni, Shigella dysenteriae, Vibrio cholerae, Vibrio parahaemolyticus, Proteus vulgaris, Bacillus cereus, Listeria monocytogenes and Clostridium botulinum) showed high sensitivity and specificity for the oligonucleotide array. Two other species (Salmonella enterica and Yersinia enterocolitica) gave weak cross-reaction with E. coli, but the reaction did not affect their detection. After redesigning the probes, positive hybridization results were obtained with Staphylococcus aureus, but not with Clostridium perfringens and Streptococcus pyogenes. The oligonucleotide array can also be applied to samples collected in clinical settings of foodborne infections. The superiority of oligonucleotide array over other tests lies on its rapidity, accuracy and efficiency in the diagnosis, treatment and control of foodborne infections.

[Fluconazole resistance in Candida albicans assayed by PCR fingerprinting with M13 prime].

OBJECTIVE: To understand the molecular and genetic mechanism underlying fluconazole resistance in Candida albicans by PCR fingerprinting with M13 primer. METHODS: Paper disc diffusion method was employed for assay of fluconazole resistance in 41 clinical isolates of Candida albicans, followed by PCR fingerprinting with M13 primer to study the gel patterns with cluster analysis using neighbor joining (NJ) method performed with RAPD200 software. RESULTS: Of the 41 clinical isolates, 11 strains (26.8%) were fluconazole-sensitive, 8 (19.5%) fluconazole-dependent and 22 (53.7%) fluconazole-resistance. Two to twelve bands could be observed among these strains, and the gel patterns revealed by cluster analysis were associated with the reactions of the strains against fluconazole and the location of infection. CONCLUSION: There is high prevalence of fluconazole resistance in clinical Candida albicans isolates, and PCR fingerprinting with M13 primer is convenient for assay of fluconazole resistance and molecular epidemiological study of Candida albicans.

Dengue virus type 2 infects human endothelial cells through binding of the viral envelope glycoprotein to cell surface polypeptides.

The endothelial cell line ECV304, derived from human umbilical cord and identified to be susceptible to dengue virus type 2 (DEN-2) infection, was used to study the molecular mechanism of DEN-2 binding to endothelial cells. DEN-2 was found by virus overlay protein-binding assays (VOPBAs) to bind to three ECV304 cell membrane proteins with molecular masses of 29, 34 and 43 kDa. Only a single protein of 29 kDa was observed when VOPBAs were carried out using preparations of trypsin-treated ECV304 cells. Pre-incubation of live ECV304 cells in culture or cell membrane proteins in modified VOPBAs with the recombinant DEN-2 envelope glycoprotein (rEgp) inhibited DEN-2 infection and blocked virus binding to the three proteins identified. These results indicate that DEN-2 rEgp could bind to three proteins on the surface of ECV304 cells. This virus-cell interaction may be associated with the receptor complex specific for DEN-2 infection of endothelial cells.

Secreted expression of dengue virus type 2 full-length envelope glycoprotein in Pichia pastoris.

The full-length envelope glycoprotein gene of dengue virus type 2 was cloned using an RT-PCR method from the infected C6/36 cells and inserted into pPICZaB vector. The recombinant plasmid was integrated into Pichia pastoris by electroporation and the expressed product was identified by SDS-PAGE and Western blotting. High-level secreted expression was performed by determining the Mut(+) phenotype and screening multi-copy integrants in the recombinant yeast cells. A recombinant protein with a molecular size of approximately 69 kDa was secreted into the supernatant from the yeast cells when induced with methanol. The expressed supernatant was able to bind with mouse polyclonal antibody or E-specific monoclonal antibody of dengue-2 virus. Purified E-poly (His)-tagged fusion protein was obtained from the expressed product by passing through a metal-chelating affinity chromatographic (MCAC) column. The results of Western blotting and solid-phase ELISA using dengue virus antibodies indicated that the purified recombinant E glycoprotein retained its antigenicity. High-level production of the recombinant E protein up to 100 mg/l indicates that P. pastoris is an efficient expression system for dengue virus full-length envelope glycoprotein.