OBJECTIVETo investigate the functional relations between the putative proteins YpCD1.08, YpCD1.09, YpCD1.16 encoded in pCD1 plasmid of Yersinia pestis and its type III secretion system (T3SS).

METHODSMutants of YpCD1.08, YpCD1.09, YpCD1.16 were constructed using λ-Red recombinant system. The growth curves of the mutant strains cultivated in TMH medium with or without calcium at 26 °C and 37 °C were determined to analyze the low calcium response phenotype. The transcription levels of ΔYpCD1.08, ΔYpCD1.09, ΔYpCD1.16 in Yersinia pestis and the dependence to temperature were determined using real time RT-PCR after cultivation at 26 °C and 37 °C and extraction of RNA. A β-lactamases reporter system was adopted to study the influence of these genes on the translocation of effector YopE of T3SS.

RESULTSWhen grown in TMH medium without calcium at 26 °C and 37 °C, the growth curve of the YpCD1.08, YpCD1.09, YpCD1.16 mutants were similar to that of the wild-type strain, indicating that the low calcium response of all the mutants were normal. The ratios of YpCD1.08, YpCD1.09, YpCD1.16 gene transcriptional level at 37 °C and 26 °C were 2.3 ± 0.3, 2.3 ± 0.5 and 3.2 ± 0.7, respectively, indicating that these genes were transcribed in Yersinia pestis and their transcription regulations showed a temperature-dependence that was consistent with the well established temperature-dependent expression of Yersinia T3SS genes. The β-lactamases reporter assays demonstrated that ΔYpCD1.08 could translocate much higher level of YopE into HeLa cells, since that the light intensity ratio of 477/520 nm at 140 min was 2.5, whereas it was 1.8 for the wild-type strain, and the values in ΔYpCD1.09 and ΔYpCD1.16 were similar to the wild-type strain.

CONCLUSIONYpCD1.08, YpCD1.09, YpCD1.16 gene are likely to be the new members of T3SS, and the putative protein YpCD1.08 could play some roles in YopE secretion and translocation.

Bacterial Outer Membrane Proteins ; secretion ; Bacterial Secretion Systems ; genetics ; Genes, Bacterial ; Plasmids ; Protein Interaction Mapping ; Yersinia pestis ; genetics ; metabolism ; pathogenicity

Bacterial Outer Membrane Proteins ; chemistry ; genetics ; physiology ; Bacteriophages ; chemistry ; Humans ; Receptors, Virus ; chemistry ; Vibrio cholerae ; virology

OBJECTIVETo construct recombinant BCG against leptospirosis.

METHODSWe amplified the entire open reading frame of the OmpL1 gene from the genome of the leptospire serovar Lai strain 017. Two recombinant plasmids pBQ1 and pBQ2 were constructed by oriented ligation based on the E. coli-BCG shuttle plasmids pMV261 and pMV361 respectively. The recombinant plasmids were transformed into BCG by electroporation. The rBCGs bearing pBQ1 and pBQ2 were induced by high temperature of 45 degrees C.

RESULTSThe expressed product, a 35kD protein was detected by SDS-PAGE. The result indicates that pBQ1 and pBQ2 can express OmpL1 in rBCG.

CONCLUSIONThe technical methods in this study may help detect the immunogenicity and immunoprotection of OmpL1 and develop more safe, highly effective rBCG bearing leptospiral antigen with long-lasting protection.

BCG Vaccine ; genetics ; Bacterial Outer Membrane Proteins ; biosynthesis ; genetics ; DNA, Bacterial ; genetics ; Gene Expression ; Genes, Bacterial ; Leptospira interrogans ; genetics ; Open Reading Frames ; genetics ; Plasmids ; Recombinant Proteins ; biosynthesis

For recent years, the research has been focused on the ina gene application in the field of biological ice nucleation. This paper reviewed the application of ina genes in bacterial cell surface display, construction of reporter gene systems, killing insect pests through induced freezing, sensitive detection of pathogenic bacteria contaminating foods, breeding of cold resistant varieties. A brief introduction of the ina gene application in killing insect pests in China was also made in this review.
Bacterial Outer Membrane Proteins ; genetics ; physiology ; Bacterial Proteins ; genetics ; physiology ; Freezing ; Insect Control ; methods ; Pseudomonas ; genetics ; Recombinant Fusion Proteins ; genetics ; Research Design

OBJECTIVETo construct prokaryotic expression systems of ltB/ctB-ompL1/1 fusion genes and to determine the L.interrogans carrying status in leptospirosis patients with the expression products.

METHODSThe fusion genes ltB-ompL1/1 and ctB-ompL1/1 were constructed using linking primer PCR method. SDS-PAGE was used to examine expression of the target recombinant proteins rLTB-rOmpL1/1 and rCTB-rOmpL1/1. Western blot and GM1-ELISA were used to measure the immunogenic and GM(1)-binding activities of rLTB-rOmpL1/1 and rCTB-rOmpL1/1, respectively. PCR and MAT were performed to detect the expression of ompL1 gene in 97 wild L.interrogans strains. Antibodies against ompL1 gene products in serum samples of 228 leptospirosis patients were detected with ELISA method.

RESULTSThe homogeneity of nucleotide and putative amino acid sequence of ltB-jompL1/1 and ctB-ompL1/1 fusion genes were 99.7 % - 99.9 % and 99.5 % - 100 %, in comparison with the reported corresponding sequences. Expression outputs of both rLTB-rOmpL1/1 and rCTB-rOmpL1/1, mainly present in inclusion body, accounted for 10% of the total bacterial protein. Both rLTB-rOmpL1/1 and rCTB-rOmpL1/1 could combine to rabbit anti-rOmpL1/1 serum and bovine GM(1). 89.7 % of L.interrogans wild strains had ompL1 gene. 87.6% of the wild L.interrogans strains presented positive results for MAT (titers :1:4-1:256) with the rabbit anti-rOmpL1/1 or anti-rOmpL1/2 sera. 86.8% and 88.6% of the patients' serum samples were positive for rOmpL1/1 and rOmpL1/2 antibodies, respectively.

CONCLUSIONThe fusion proteins, rLTB-rOmpL1/1 and rCTB-rOmpL1/1, showed high immunogenic and GM(1)-binding activities. ompL1 gene is extensively distributed and frequently expressed in different serogroups of L.interrogans and its products expressed by different genotypes exhibit extensive cross-antigenicity.

Bacterial Outer Membrane Proteins ; genetics ; immunology ; Bacterial Toxins ; genetics ; Bacterial Vaccines ; genetics ; Cloning, Molecular ; Enterotoxins ; genetics ; Escherichia coli Proteins ; genetics ; Genes, Bacterial ; genetics ; Humans ; Leptospira interrogans ; genetics ; immunology ; Prokaryotic Cells ; metabolism ; Recombinant Fusion Proteins ; genetics ; immunology ; Vaccines, Synthetic ; genetics

This study was aimed to construct a prokaryotic expressing vector of Hap gene from Nontypeable Haemophilus influenzae, and express and identify the fusion proteins of Hap-His in E. coli. The gene encoding protein Hap was amplified from Nontypeable Haemophilus influenzae ATCC49247 chromosomal DNA by PCR, then it was cloned into prokaryotic expression plasmid pET-32a (+). The recombinant plasmid pET-32a(+)-Hap was transformed into E. coli BL21 and expression was induced by Isopropy-beta-D-thiogalatoside(IPTG). The Hap-His fusion protein expressed so was analyzed by SDS-PAGE and Western-blot. The results showed that the recombinant expressive plasmid pET-32a (+)-Hap was constructed successfully, and the recombinant plasmid expressed Hap-His fusion protein with relative molecule mass 176 000 and mainly existed in inclusion body. This fusion protein could combine with anti-His monoclonal antibody specifically through Western blot analysis. Successful expression of Hap-His fusion protein in prokaryotic cell could lay a basis for further study of immunocompetence of Hap protein and development of NTHi vaccine.
Bacterial Outer Membrane Proteins ; biosynthesis ; genetics ; Cloning, Molecular ; Escherichia coli ; genetics ; metabolism ; Genetic Vectors ; genetics ; Haemophilus influenzae ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; Serine Endopeptidases ; biosynthesis ; genetics

OBJECTIVETo determine expression changes of major outer membrane protein(OMP) antigens of Leptospira interrogans serogroup Icterohaemorrhagiae serovar Lai strain Lai during infection of human macrophages and its mechanism.

METHODSOmpR encoding genes and OmpR-related histidine kinase (HK) encoding gene of L.interrogans strain Lai and their functional domains were predicted using bioinformatics technique. mRNA level changes of the leptospiral major OMP-encoding genes before and after infection of human THP-1 macrophages were detected by real-time fluorescence quantitative RT-PCR. Effects of the OmpR-encoding genes and HK-encoding gene on the expression of leptospiral OMPs during infection were determined by HK-peptide antiserum block assay and closantel inhibitive assays.

RESULTSThe bioinformatics analysis indicated that LB015 and LB333 were referred to OmpR-encoding genes of the spirochete, while LB014 might act as a OmpR-related HK-encoding gene. After the spirochete infecting THP-1 cells, mRNA levels of leptospiral lipL21, lipL32 and lipL41 genes were rapidly and persistently down-regulated (P <0.01), whereas mRNA levels of leptospiral groEL, mce, loa22 and ligB genes were rapidly but transiently up-regulated (P<0.01). The treatment with closantel and HK-peptide antiserum partly reversed the infection-based down-regulated mRNA levels of lipL21 and lipL48 genes (P <0.01). Moreover, closantel caused a decrease of the infection-based up-regulated mRNA levels of groEL, mce, loa22 and ligB genes (P <0.01).

CONCLUSIONExpression levels of L.interrogans strain Lai major OMP antigens present notable changes during infection of human macrophages. There is a group of OmpR-and HK-encoding genes which may play a major role in down-regulation of expression levels of partial OMP antigens during infection.

Antigens, Bacterial ; genetics ; metabolism ; Bacterial Outer Membrane Proteins ; genetics ; metabolism ; Cell Line ; Chaperonin 60 ; genetics ; metabolism ; Humans ; Leptospira interrogans ; genetics ; immunology ; pathogenicity ; Lipoproteins ; genetics ; metabolism ; Macrophages ; microbiology

An isolated virulence Riemerella anatipestifer strain passaged 200 times on TSB agar were used for the virulent to avirulent conversion. The effects of passage on biological properties of outer membrane proteins (OMPs) were investigated using the virulent and avirulent strains. Transmission electron microscopy demonstrated that the avirulent strain produced lower amounts of outer membrane vesicles and the outer membrane decreased, the cytoplasmic appearance jumbled. The OMPs of the virulent strain agglutinated only in RA serotype 2 antisera, whereas the OMPs of the avirulent strain agglutinated in antisera of RA 1, 2, 10 and 11. SDS-PAGE Analysis showed the OMPs profiles of both strains were similar but the immunoblotting profiles were different. The protective immunity against Riemerella anatipestifer infection was investigated by immunizations with OMPs in ducks. ELISA results showed that the OMPs induced the production of antibodies in immunized ducks, but the OMPs of virulence strain induced higher antibody titers than the attenuated strain (P < 0.05). RA2 group showed significantly higher survival rates (100%) than RA200 group (0%) after challenged with the homologous virulent strain. The ompA gene of both stains were also amplified by PCR, nucleotide homology was 99.9%. In conclusion, OMPs of virulent RA strain are suitable candidates for vaccine development. Biological properties of OMPs undergoes significant changes during serial passage and suggest that vigilance should be used when extrapolating data obtained from the study of high-passage strains.
Animals ; Bacterial Outer Membrane Proteins ; chemistry ; genetics ; immunology ; Ducks ; Flavobacteriaceae ; chemistry ; classification ; immunology ; Flavobacteriaceae Infections ; immunology ; microbiology ; veterinary ; Serotyping

OBJECTIVETo analyze factors related to the virulence associated genes of Leptospires.

METHODSTwelve putative virulence associated genes were detected by polymerase chain reaction (PCR) method in 38 reference strains, 81 field strains of Leptospira interrogans isolated from patients or animals, and 12 avirulent strains of Leptospira biflexa.

RESULTSThese putative virulent genes were widely distributed among the strains of Leptospira interrogans, but only few of them were detected in Leptospira biflexa. Gene lipL32 was detected in all strains of Leptospira interrogans. Distribution of gene lipL36 was varied significantly with detected rates from 0 to 90.91%. Gene la1608 had a positive rate of 87.50% for strains of serogroup Icterohaemorrhagiae, but was only detected in few strains of other serogroups with a range from 0 to 25.00%. Rate of detection on gene sphA was 17.65% in Leptospira interrogans, and was absent in serovar hardjo reference strain.

CONCLUSIONResults indicated that these genes might be of importance for the virulence and pathogenicity of Leptospira interrogans, while gene lipL32 might be one of the common antigens. Gene lipL36 might be involved in serogroup specificity with genetic diversity, but gene la1608 was as one of the genes with specificity for serogroup Icterohaemorrhagiae. However, serovar hadjo might hold quite different genetic characteristics when compared with the other serovars of Leptospires.

Bacterial Outer Membrane Proteins ; genetics ; Bacterial Proteins ; genetics ; Carbohydrate Dehydrogenases ; genetics ; Flagellin ; genetics ; Genes, Bacterial ; genetics ; Hemolysin Proteins ; genetics ; Leptospira ; genetics ; pathogenicity ; Lipoproteins ; genetics ; Polymerase Chain Reaction ; Virulence ; genetics ; Virulence Factors ; genetics

OBJECTIVETo understand the distribution of emm gene types related to group A streptococcus-caused scarlet fever among children in Beijing and to analyze the relationship between the mutation of the emm types and scarlet fever.

METHODSNasopharyngeal swab samples were collected from the scarlet fever cases diagnosed in 36 hospitals in Beijing to isolate the GAS strains from May to July, betgween 2011 and 2014. Genotyping of emm gene was performed with PCR and N-terminal gene fragments of M protein were sequenced. Data of all the scarlet fever cases in Beijing that reported through the National Notifiable Infectious Disease Surveillance System (NNIDSS) , were gathered and analyzed.

RESULTSAmong the collected 2 161 nasopharyngeal swabs, 762 GAS strains were identified (35.3%). In addition, 7 emm types were detected, in which emm12 accounted for 69.4% (529/762) , emm1 accounted for 29.8% (227/762) , and other five types (emm 11, 22, 75, 89, and 128) accounted for 0.8% (6/762) , respctively. Compared with the emm types detected between 2011 and 2014, emm12, emm1 and other types accounted for 82.2% (295/359) , 16.7% (60/359) and 1.1% (4/359, including emm11, 22 and 89) in 2011 respectively.emm12, emm1 and emm75 accounted for 77.3% (123/163) , 23.9% (39/163) and 0.6% (1/163) respectively in 2012. emm12 and emm1 accounted for 50.7% (38/75) and 49.3% (37/75) in 2013 while emm12, emm1 and emm128 accounted for 44.2% (73/165) , 55.2% (91/165) and 0.6% (1/165) respectively in 2014. The differences of the constitution of emm types from 2011 to 2014 appeared statistically significant (P<0.001). In 2011 and 2012, major type appeared as emm12, but in 2014, emm1 became predominant. A total of 6 152 cases were reported in 2011, while 2 908, 2 048 and 3 918 cases were reported in 2012, 2013 and 2014 respectively. Age specific differences were noticed in the distribution of emm types GAS strains in 2011, with the number of emm12 strains detected higher in 1-5 year olds than in age group > 5 years (P<0.05). There were area specific differences in distribution of emm types of GAS strains seen in 2011 and 2013. In 2011, the number of emm1 strains detected in urban area was higher than in suburb area (P<0.05). However, in 2013, the number of emm1 strains detected in suburb area was seen higher than in urban area (P< 0.05).

CONCLUSIONGAS with emm12 and GAS emm1 appeared interchangeably predominant in Beijing from 2011 to 2014. Changes in predominant emm types seemed also related to the trends of incidence rates on scarlet fever.

Antigens, Bacterial ; Bacterial Outer Membrane Proteins ; Beijing ; epidemiology ; Carrier Proteins ; Child ; Genotype ; Humans ; Mutation ; Scarlet Fever ; epidemiology ; genetics ; Streptococcus pyogenes ; classification ; genetics ; isolation & purification