Comparison Of GalE, Cj1136, Cj1138 And Cj1139 Genes Among Campylobacter Jejuni Strains

Objective: Campylobacter jejuni (C. jejuni) is the predominant cause of bacterial gastroenteritis in the world and Guillain-Barre syndrome (GBS) is a peripheral neuropathy happened after C.jejuni infection. According to different pathological and physiological representation, GBS can be classified into acute demyelinating pattern (AIDP), acute motor axonal neuropathy (AMAN) and Miller-Fisher syndrome (MFS). There have been 5 complete genome sequence published in GeneBank, sincen 2000. Many researches indicate that molecular mimicry of Campylobacter jejuni lipo-oligosaccharides (LOS) with gangliosides in nervous tissue is considered to be involved in the pathogenesis of C.jejuni-induced GBS.In this reseach, the galE, Cj1136, Cj1138 and Cj1139 genes cluster of three C. jejuni isolates from north China which have been proved can cause AMAN type GBS were cloned and sequenced. The nucleotide sequences were analyzed and compaired with the known sequences of C. jejuni strains in Genbank to find out the relevance between the sequence character and ability to cause GBS as also as the markers for local GBS associated C.jejuni.Methods: Bacteria culture: The C. jejuni strains used were isolated from stools of AMAN patients from North China.The serotypes are respectively Penner O:19, Penner O:2, Penner O:5. Growth condition was following the procedure of Li CY et al.DNA isolation: DNA was isolated using the Wizard Genomic DNA Purification Kit (Promega).Sequence and assemblte: All the PCR products sequenced byAnalytical Genetics Technology Centre, University Health Network, Toronto Princess Margaret Hospital and Huada Gene Laboratory of Shenzhen. Sequencing results were spliced and assembled into a complete sequence by the terminals overlapped each other with the known genome sequence NCTC11168 as template.Evolutionary analysis: The evolutionary distances from nucleotide sequences were estimated for the galE, Cj1136, Cj1138, Cj1139 sequences of the three C. jejuni strains and the corresponding sequence of C.jejuni stains whose genome sequence have published in GeneBank and the phylogenetic tree was constructed using Mega version 4 software.Results : The galE, Cj1136, Cj1138 and Cj1139 gene of the three GBS- associated C. jejuni strains were composed by 987 base pairs , 1173 base pairs, 1170 base pairs, 912 base pairs respectively. The alignment with the related sequence of NCTC11168 showed that there were 4 same mutations in the galE gene and 2 same mutations in the Cj1138 gene of the three C. jejuni stains. Data from phylogenetic analysis of Cj1138 demonstrated that the three C. jejuni strains were genetically closed to NCTC11168, with the biggest phylogenetic distance between the three of them was 2.1%.The variation frequency of galE sequences of GBS- associated C. jejuni were higher than that of non-GBS- associated C.jejuni. The phylogenetic analysis demonstrated that each of the three C.jejuni stains was separately genetically closed to three stains which sequences have published in GenBank. The phylogenic tree reflected the regional feature of C.jejuni .Conclusions:The probability of sequence variation of galE, Cj1138 of GBS- associated C.jejuni is significantly higher than non-GBS-associated C. jejuni strains, the relation between the variation and GBS-pathogenesis remains to be further confirmed. The mutations found in the three C.jejuni stains established the foundation for exploring the biologically characteristic of GBS-associated C.jejuni stains.