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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The suitability of urine specimens for the detection of Chlamydia trachomatis infections in men was assessed. Urethral swabs from 301 patients were cultured for C. trachomatis, and the results were compared with results obtained from Chlamydiazyme. The results of 298 specimens were also compared with results obtained from PCR analysis of first-void urine specimens. The sensitivity of confirmed Chlamydiazyme analysis was 93% and the specificity was greater than 99% compared with culture. The sensitivity of the PCR method was 100% compared with culture. Chlamydia trachomatis was detected by PCR in an additional three specimens from which C. trachomatis could not be cultured. Urine appears to be an appropriate specimen for the detection of C. trachomatis antigens and nucleic acids.
Mol Cell Probes 1993 Dec
PMID:Detection of Chlamydia trachomatis in urine using enzyme immunoassay and DNA amplification. 814 73

A sulphated glycosaminoglycan-dependent mechanism of microbial infection for mammalian cells was characterized for the Chlamydia trachomatis trachoma and lymphogranuloma venereum (LGV) biovars. We demonstrated that the trachoma and LGV biovars compete for the same receptor(s) on host cells and that their infectivity was inhibited by heparin or heparan sulphate. Using a specific heparan sulphate lyase (heparitinase) to treat organisms, the infectivity of both biovars was abolished. Furthermore, exogenous heparan sulphate rescued chlamydial infectivity following treatment with heparitinase and the restored infectivity was neutralized by an anti-heparan sulphate monoclonal antibody. These data suggest that heparan sulphate-like-mediated interactions between C. trachomatis and eukaryotic cells are essential for infectivity.
Mol Microbiol 1994 Feb
PMID:Trachoma and LGV biovars of Chlamydia trachomatis share the same glycosaminoglycan-dependent mechanism for infection of eukaryotic cells. 815 74

In this study we investigate the 57 kD heat shock protein of Chlamydia trachomatis for potential HLA-B27 restricted T cell epitopes. This protein is known to elicit T cell immunity, as judged by delayed type hypersensitivity. We synthesized 24 peptides containing the B27 anchor amino acid arginine at position 2, according to the rules previously described for peptide binding to MHC class I molecules. The nonamer peptides were tested in an in vitro assembly assay; six out of the 24 peptides bind to HLA-B27 although their sequences only partially match the HLA-B27 binding motif. Two of these six peptides carry negatively charged amino acids which apparently fit into the P1 pocket and in three out of the six a positively charged amino acid fits into the P3 pocket. In addition, two octamer peptides stabilized the HLA-B27 molecule without containing an appropriate amino or carboxy terminus. Therefore our data suggest that current binding rules will need to be refined before they can be used to accurately predict potential T cell epitopes. Furthermore our HLA-B27-binding peptides should prove useful probes for the study of the processing and presentation of this bacterial antigen, and of changes in the T cell repertoire induced by this form of infection.
Mol Immunol 1994 Apr
PMID:HLA-B27 binding peptides derived from the 57 kD heat shock protein of Chlamydia trachomatis: novel insights into the peptide binding rules. 815 35

Characterization of the genes involved in the process of protein translocation is important in understanding their structure-function relationships. However, little is known about the signals that govern chlamydial gene expression and translocation. We have cloned a 1.7 kb HindIII-PstI fragment containing the secY gene of Chlamydia trachomatis. The complete nucleotide sequence reveals three open reading frames. The amino acid sequence shows highest homology with Escherichia coli proteins L15, SecY and S13, corresponding to the spc-alpha ribosomal protein operons. The product of the C. trachomatis secY gene is composed of 457 amino acids with a calculated molecular mass of 50,195 Daltons. Its amino acid sequence shows 27.4% and 35.7% identity to E. coli and Bacillus subtilis SecY proteins, respectively. The distribution of hydrophobic amino acids in the C. trachomatis secY gene product is suggestive of it being an integral membrane protein with ten transmembrane segments, the second, third and seventh membrane segments sharing > 45% identity with E. coli SecY. Our results suggest that despite evolutionary differences, eubacteria share a similar protein export apparatus.
Mol Gen Genet 1994 May 25
PMID:Cloning and characterization of a secY homolog from Chlamydia trachomatis. 820 93

The aim of this study was to compare culture and polymerase chain reaction techniques in detection of Chlamydia trachomatis in clinical specimens. Two hundred clinical specimens previously examined for C. trachomatis by culture were analysed blindly by polymerase chain reaction. A 144 bp fragment of DNA from the MOMP of C. trachomatis was amplified. In addition, a 250 bp segment of beta-globin gene was amplified as an internal control. In 27 culture negative specimens, the beta-globin amplicon was not detected. Of the 173 specimens assessable by PCR, 24 (13.8%) were positive by both methods. Four specimens were positive by PCR and negative by culture. Three were collected post-antibiotic treatment; two were from previous culture-proven chlamydia infection suggestive of the presence of DNA of non-viable organisms, and one case was toxic by culture. No specimen was positive by culture and negative by PCR. Overall PCR when compared to culture had a sensitivity of 100% and specificity of 97.3% with positive and negative predictive values of 85.7% and 100%, respectively. PCR is especially useful when culture results can not be confirmed due to toxicity, inadequate transport or insufficient specimen collected.
Mol Cell Probes 1993 Oct
PMID:Comparison of polymerase chain reaction and culture techniques for detection of Chlamydia trachomatis. 826 69

Restriction fragments containing the major outer-membrane protein (MOMP) gene from two nonhuman (rodent) strains of Chlamydia trachomatis, the mouse pneumonitis (MoPn) strain and the SFPD strain isolated from hamsters with transmissible proliferative ileitis, were cloned and sequenced. The MOMP genes of both MoPn and SFPD encode an identical 22-amino acid leader peptide and mature polypeptides of 365 and 382 amino acids, respectively. Alignment of the MOMP genes of the two rodent strains revealed 91% identity. By comparison with other known chlamydial MOMP gene sequences, there was 80%-83% identity with human biovars strains of C. trachomatis, and there was 69%-70% identity with C. psittaci and C. pneumoniae strains. The main differences in these sequences were clustered into four variable domains. A minimum-length evolutionary tree was constructed on the basis of the MOMP gene variable positions by using PIMA package software. The minimum mutation distances indicated that (i) the MOMP genes of all chlamydial strains may have evolved from a common ancestor; (ii) all the strains of C. trachomatis compose one of the subtrees, and strains of C. psittaci and C. pneumoniae compose the other subtree; and (iii) in the C. trachomatis subtree, the human and the rodent strains are divided into two clusters. The branching pattern of this evolutionary tree is generally consistent with current classification based on serological, morphological, and other biological characteristics.
Mol Biol Evol 1993 Nov
PMID:Comparison of the major outer-membrane protein (MOMP) gene of mouse pneumonitis (MoPn) and hamster SFPD strains of Chlamydia trachomatis with other Chlamydia strains. 827 58

Using well-characterized mutant host cell lines, deficient in specific enzymes of energy and nucleotide metabolism, we addressed numerous questions regarding nucleotide metabolism in the obligate intracellular bacterium Chlamydia trachomatis. The results presented indicate that C. trachomatis: (i) does not absolutely depend on mitochondrial generated ATP for survival; (ii) does have a significant draw on host-cell NTP pools but does not have a detrimental effect on the ability of the host cell to maintain its energy charge; (iii) lacks the ability to synthesize purine and pyrimidine nucleotides de novo; (iv) is not capable of interconverting purine nucleotides; and (v) possesses the pyrimidine metabolic-pathway enzymes CTP synthetase and deoxycytidine nucleotide deaminase. In total our results indicate that C. trachomatis is auxotrophic for host-cell ATP, GTP and UTP. In contrast, CTP can be obtained from the host cell or it can be synthesized from UTP by the parasite.
Mol Microbiol 1993 Jun
PMID:The obligate intracellular bacterium Chlamydia trachomatis is auxotrophic for three of the four ribonucleoside triphosphates. 836 55

Chlamydiae are obligate intracellular bacteria which undergo a unique developmental cycle, alternating between non-replicative elementary bodies (EBs) and replicative reticulate bodies (RBs). The transition from RB to EB is characterized by condensation of the chromosome into a dense nucleoid structure. The chlamydial histone homologue Hc1 is sufficient to induce formation of a similar structure in Escherichia coli. High-level Hc1 expression in E. coli is self-limiting and down-regulates transcription, translation, and replication at concentrations similar to those observed in chlamydial elementary bodies. Expression of Hc1 at sub-structural levels may have specific regulatory functions through its interaction with chromosomal DNA. In E. coli this is reflected in a dramatic shift in the pattern of gene expression. The differential expression of the outer membrane porin proteins OmpC and OmpF and analysis of lacZ fusions with promoter regions sensitive to supercoiling suggests that low-level Hc1 expression results in a net relaxation of chromosomal DNA. Topological analysis of plasmid DNA from both E. coli and Chlamydia trachomatis supports a decrease in superhelicity preceding nucleoid formation. In vitro analysis of purified Hc1-DNA interactions supports preferential binding based upon DNA conformation. These results suggest a dual role in which Hc1-mediated changes in gene expression may precede metabolic inactivity.
Mol Microbiol 1993 Jul
PMID:Hc1-mediated effects on DNA structure: a potential regulator of chlamydial development. 841 80

Extracts of Chlamydia psittaci and Chlamydia trachomatis were used to transcribe molecularly cloned chlamydial genes in vitro. The extracts were prepared by lysing reticulate bodies, obtaining the 10,000 x g centrifugation pellet, and eluting RNA polymerase from the pellet by treatment with 2M KCl to yield a fraction designated SS2. Some in vitro transcription was initiated from non-chlamydial promoters and a small amount of transcription was from endogenous DNA template in SS2. However, optimal transcription from exogenous templates required chlamydial promoter sequences, and primer extension analysis indicated that chlamydia promoter-specific in vitro transcription was initiated from the same start sites recognized in vivo. A monoclonal antibody that was generated against Escherichia coli sigma 70 and which immunologically cross-reacts with C. trachomatis sigma 66 inhibited in vitro transcription of vector and cloned chlamydial DNA, suggesting that transcriptional initiation in the SS2 fraction is mediated by sigma 66. An in vitro transcription assay based on detection of transcripts of specific lengths was applied to the chlamydial system; this assay and others described here should be useful in defining chlamydial promoters and other transcriptional regulatory elements.
Mol Microbiol 1993 Mar
PMID:In vitro transcription in Chlamydia psittaci and Chlamydia trachomatis. 848 21

Peptides representing the Chlamydia trachomatis major outer membrane protein variable domains (VD) 1 and 4 of serovars C and E, respectively, have been shown to elicit a neutralizing antibody response in mice. To assess whether the position within a chimeric peptide influences the immunogenicity of the epitopes, two constructs, VD 1-4 and VD 4-1, were made in which the position of the VD relative to the amino and carboxy terminals were rotated. C57BL/10 mice were immunized with 100 micrograms of peptide in complete Freund's adjuvant (FA) on day 0, followed by an immunization with peptide (100 micrograms) in complete FA on day 14. By day 21 the immunodominant epitope in both chimeras as measured by ELISA was the one located at the carboxy terminus. A pepscan of the VD 1-4 antisera revealed a main peak in VD 4 which had been previously identified by neutralizing MAbs. The VD 4-1 antisera gave a peak in the VD 1 region which did not correspond to regions previously mapped with neutralizing MAbs. The VD 1-4 antisera but not the VD 4-1 antisera was able to neutralize in vitro serovar E. In summary, the position of these chlamydial epitopes within a chimeric peptide greatly influenced the resulting immune response.
Mol Immunol
PMID:The effect of orientation within a chimeric peptide on the immunogenicity of Chlamydia trachomatis epitopes. 867 84


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