ABSTRACT
The allelic diversity and population structure of Campylobacter jejuni were studied by multilocus nucleotide sequence analysis. Sequences from seven housekeeping genes were obtained from 32 C. jejuni isolates isolated from enteritis patients in Germany, Hungary, Thailand, and the United States. Also included was strain NCTC 11168, the complete genomic sequence of which has recently been published. For all loci analyzed, multiple strains carried identical alleles. The frequency of synonymous and nonsynonymous sequence polymorphisms was low. The number of unique alleles per locus ranged from 9 to 15. These alleles occurred in 31 different combinations (sequence types), so that all but two pairs of strains could be distinguished from each other. Sequences were analyzed for evidence of recombination by the homoplasy test and split decomposition. These analyses showed that intraspecific recombination is frequent in C. jejuni and has generated extensive diversity of allelic profiles from a small number of polymorphic nucleotides.
Subject(s)
Alleles , Campylobacter jejuni/classification , Campylobacter jejuni/genetics , Genetic Variation , Recombination, Genetic , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Bacterial Typing Techniques , Campylobacter Infections/microbiology , Chromosome Mapping , Enteritis/microbiology , Genes, Bacterial , Humans , Linkage Disequilibrium , Molecular Sequence Data , Phylogeny , Sequence Analysis, DNAABSTRACT
A new electrochemical device, the scanning droplet cell, is presented. Small electrolyte droplets are positioned on the sample surface and enable a spatially resolved surface analysis or modification. The droplet is simply held by its surface tension and, therefore, no surface pretreatment is necessary. According to the conventional 3-electrode arrangement all common potentiostatic and galvanostatic techniques, e.g. impedance spectroscopy, cyclic voltammetry, or current transients of potentiostatic steps, are possible.
