Biochim Biophys Acta 1998,

1372:311–322.CrossRefPubMed 36. Laemmli UK: Cleavage of structural R428 clinical trial proteins during the assembly of the head of bacteriophage T4. Nature 1970, 227:680–685.CrossRefPubMed 37. Kremling A, Heermann R, Centler F, Jung K, Gilles ED: Analysis of two-component signal transduction by mathematical modeling using the KdpD/KdpE system of Escherichia coli. Biosystems 2004,78(1–3):23–37.CrossRefPubMed 38. Epstein W, Kim BS: Potassium transport loci in Escherichia coli K-12. J Bacteriol 1971, 108:639–644.PubMed 39. Miller JH: Experiments in Molecular Genetics. A short course in bacterial genetics (Edited by: Miller JH). Cold Spring Harbor, NY: Cold Spring Harbor Adriamycin price Laboratory Press 1992, 72–74. 40. Peterson GL: A simplification of the protein assay method of Lowry, et al. which is more generally applicable. Anal Biochem 1977, 83:346–356.CrossRefPubMed 41. Voelkner P, Puppe W, Altendorf K: Characterization of the KdpD protein, the sensor kinase of the K + -translocating Kdp system of Escherichia coli. Eur J Biochem 1993, 217:1019–1026.CrossRefPubMed Authors’ contributions RH and KJ designed research experiments; ML constructed the kdpD-hybrid genes; RH and ML performed experiments and analyzed data. KJ and RH wrote the manuscript. All authors have read and approved the final manuscript.”
“Background Vibrio cholerae is the causative agent of the diarrheal disease cholera.

Out of the 200 serogroups of V. cholerae, only two biotypes of serogroup O1 (classical and El Tor) and serogroup O139 cause severe PI3K Inhibitor high throughput screening Tolmetin diarrhea and epidemic cholera [1], although not all strains in these two serogroups are pathogenic. Toxigenic and nontoxigenic V. cholerae strains are genetically diverse. The toxigenic strains form a genetically homogenous group, while nontoxigenic strains are heterogeneous and may have diverse origins [2–4]. The nontoxigenic strains, which are usually isolated from environmental sources such as sewage, oysters, and brackish water, do not carry cholera toxin (CT) and other major virulence genes necessary for human pathogenesis [5]. V. cholerae is capable

of metabolizing many types of carbohydrates. Previously, we found that not only is D-sorbitol metabolized by V. cholerae, but it is also fermented at different rates by the toxigenic and nontoxigenic El Tor strains. The toxigenic strains have a low sorbitol fermentation rate and are called slow-fermenting strains, whereas the nontoxigenic strains have a faster sorbitol fermentation rate and are called fast-fermenting strains [6]. The sorbitol fermentation test is included in the Phage-biotyping scheme, which consists of phage typing and biochemical typing and is developed in 1970s in China. This scheme is used to distinguish and type the El Tor strains which are pathogenic and are potential to cause epidemic or not [6].