Objective To explore the molecular mechanisms involved in hypokalemic salt-losing tubulopathies ( SLTs) through genetic screening of WNK gene in patients with SLTs. Methods Forty-four kindreds of SLTs were diagnosed Batter's syndrome or Gitelman's syndrome after CLCNKB and SLC12A3 sequencing and analysis, 8 of whose phenotype can not be simply attributed to CLCNKB or SLC12A3 mutations. Primers for PCR-amplified exons of WNK4 and WNK1 gene in genomic DNA were designed, and direct sequencing was performed to analyse the PCR products. Results Two missense mutations of WNK1, Ile~(1172)→ Met (I1172M) and Ser~(2047) → Asn (S2047N), were identified. Both of these 2 mutations segregated with the disease in SLTs kindred. Conclusion Two heterozygote missense mutations of WNK1 gene (I1172 M and S2047N) were found in 8 SLTs kindreds, indicating that WNK1 might be another gene responsible for hypokalemic salt-losing tubulopathies.

In this study, we investigated the mechanism of transformation by Bacillus subtilis strain 168 by proteomic analysis. B. subtilis strain 168 was able to stereoselectively transform cis-propenylphosphonic acid (cPPA) to fosfomycin. The maximal fosfomycin production was 816.6 microg/mL after two days cultivation, with a conversion rate of 36.05%. We separated the whole cellular proteins by two-dimensional gel electrophoresis (2-DE) method, and 562 protein spots were detected in the presence of cPPA in the medium, while 527 protein spots were detected in the absence of cPPA. Of them, 98 differentially expressed protein spots were found. Among them, 52 proteins were up-regulated whereas 20 were down-regulated in the presence of cPPA in the medium, and 26 induced at the presence of cPPA. The differentially expressed proteins were analyzed by combined MS and MS/MS methods. Eighty protein spots, including 45 up-regulated proteins, 17 down-regulated proteins, and 18 induced by cPPA were identified. Based on the results of proteomic analysis, we postulated two steps of transformation: in the first step, cPPA was hydrated to 2-hydroxypropylphosphonic acid; in the second step, 2-hydroxypropylphosphonic acid was transformed to fosfomycin via a dehydrogenation reaction.
Bacillus subtilis ; genetics ; growth & development ; metabolism ; Bacterial Proteins ; metabolism ; Biotransformation ; Fosfomycin ; metabolism ; Organophosphorus Compounds ; metabolism ; Proteome ; metabolism ; Proteomics