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- Falk, Lars, et al.
(author)
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Genotyping of Chlamydia trachomatis would improve contact tracing
- 2003
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In: Sexually Transmitted Diseases. - : Ovid Technologies (Wolters Kluwer Health). - 0148-5717 .- 1537-4521. ; 30:3, s. 205-210
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Journal article (peer-reviewed)abstract
- Background: The reported number of genital Chlamydia trachomatis infections has increased 15% annually since 1997 in Sweden. Inaccurate partner notification might be one reason.Goal: The goals were to determine if genotyping of C trachomatis would improve partner notification and to study the duration of infection.Study Design: Sexual networks were constructed. C trachomatis isolates from 231 individuals attending the Örebro STD clinic during 1 year were typed by sequencing of the omp1 gene.Results: All individuals were traced and diagnoses were established in 30 of 161 networks. More than one genotype was seen in seven networks. The mean duration of C trachomatis infection in each network was calculated to be 23 weeks.Conclusion: Genotyping could be a useful tool in partner notification when there are discrepant or uncommon genotypes. Limited clinic catchment areas create information difficulties that obstruct accurate contact tracing.
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- Gräslund, Susanne, et al.
(author)
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A novel affinity gene fusion system allowing protein A-based recovery of non-immunoglobulin gene products
- 2002
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In: Journal of Biotechnology. - 0168-1656 .- 1873-4863. ; 99:1, s. 41-50
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Journal article (peer-reviewed)abstract
- An expression vector system has been developed, taking advantage of a novel, Staphylococcus aureus protein A (SPA)-binding affinity tag ZSPA-1, enabling straightforward affinity blotting procedures and efficient recovery by affinity purification of expressed gene products on readily available reagents and chromatography media. The 58 amino acid SPA-binding affinity tag ZSPA-1, was previously selected from a library constructed by combinatorial mutagenesis of a protein domain from SPA. An Escherichia coli expression vector for intracellular T7 promoter (PT7) driven production was constructed with an N-terminal dual affinity tag, consisting of a hexahistidyl (His6) tag in frame with the ZSPA-1 tag, thus allowing alternative affinity recovery methods. To evaluate the system, five cDNA clones from a mouse testis cDNA library were expressed, and two alternative blotting procedures were developed for convenient screening of expression efficiencies. The five produced fusion proteins were recovered on both immobilized metal-ion affinity chromatography (IMAC) columns and on Protein A-based chromatography media, to allow comparative studies. It was found that the Protein A-based recovery resulted in the highest degree of purity, and furthermore, gene products that were produced as inclusion bodies could after denaturation be efficiently affinity purified on Protein A-Sepharose in the presence of 0.5 M guanidine hydrochloride. The convenience and robustness of the presented expression system should make it highly suitable for various high-throughput protein expression efforts.
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- Jurstrand, Margaretha, et al.
(author)
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Characterization of Chlamydia trachomatis omp1 genotypes among sexually transmitted disease patients in Sweden
- 2001
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In: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 39:11, s. 3915-3919
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Journal article (peer-reviewed)abstract
- A method for detection and genotyping of genital Chlamydia trachomatis infections based on omp1 gene amplification and sequencing was developed. DNA was extracted from urogenital or urine samples using a Chelex-based method, and an approximately 1,100-bp-long fragment from the omp1 gene was directly amplified and sequenced. Genotyping was performed by BLAST similarity search, and phylogenetic tree analysis was used to illustrate the evolutionary relationships between clinical isolates and reference strains. The method was used to determine the genotypes of C. trachomatis in 237 positive urogenital and/or urine specimens collected at a Swedish sexually transmitted disease clinic during 1 year. The most common genotypes corresponded to serotypes E (47%) and F (17%). The omp1 gene was highly conserved for genotype E (106 of 112 samples without any mutation) and F (41 of 42 samples without any mutation) strains but appear slightly less conserved for genotypes G (n = 6) and H (n = 6), where the sequences displayed one to four nucleotide substitutions relative to the reference sequence. Genotyping of samples collected at the follow-up visit indicated that two patients had become reinfected, while three other patients suffered treatment failure or reinfection. One woman appeared to have a mixed infection with two different C. trachomatis strains. This omp1 genotyping method had a high reproducibility and could be used for epidemiological characterization of sexually transmitted Chlamydia infections.
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