The suhB gene is located at 55 min on the Escherichia coli chromosome and encodes a protein of 268 amino acids. Mutant alleles of suhB have been isolated as extragenic suppressors for the protein secretion mutation (secY24), the heat shock response mutation (rpoH15), and the DNA synthesis mutation (dnaB121) (K. Shiba, K. Ito, and T. Yura, J. Bacteriol. 160:696-701, 1984; R. Yano, H. Nagai, K. Shiba, and T. Yura, J. Bacteriol. 172:2124-2130, 1990; S. Chang, D. Ng, L. Baird, and C. Georgopoulos, J. Biol. Chem. 266:3654-3660, 1991). These mutant alleles of suhB cause cold-sensitive cell growth, indicating that the suhB gene is essential at low temperatures. Little work has been done, however, to elucidate the role of the product of suhB in a normal cell and the suppression mechanisms of the suhB mutations in the aforementioned mutants. The sequence similarity shared between the suhB gene product and mammalian inositol monophosphatase has prompted us to test the inositol monophosphatase activity of the suhB gene product. We report here that the purified SuhB protein showed inositol monophosphatase activity. The kinetic parameters of SuhB inositol monophosphatase (K m ؍ 0.071 mM; V max ؍ 12.3 mol/min per mg) are similar to those of mammalian inositol monophosphatase. The ssyA3 and suhB2 mutations, which were isolated as extragenic suppressors for secY24 and rpoH15, respectively, had a DNA insertion at the 5 proximal region of the suhB gene, and the amount of SuhB protein within mutant cells decreased. The possible role of suhB in E. coli is discussed.The suhB gene was first identified as the locus for the ssyA3(Cs) mutation that was isolated as an extragenic suppressor for the secY24(Ts) mutant (31). The ssyA3 mutation restored the defect in protein secretion caused by the secY24 mutation (33) and rescued the temperature-sensitive cell growth of secY24 mutant cells. The ssyA3 mutation caused cold-sensitive cell growth by itself and impaired protein synthesis was observed in the ssyA3 mutant at low temperatures (31). The cold-sensitive growth of the ssyA3 mutant was rescued by introduction of the wild-type copy of suhB, indicating that ssyA3 is a mutant allele of suhB (40). The suhB2(Cs) mutation is another allele of suhB and was isolated as an extragenic suppressor of the rpoH15(Ts) mutation. The rpoH15 mutant gene produces an altered 32 protein and causes a defect in the induction of heat shock proteins at higher temperatures (42). The suhB2(Cs) mutation rescued the temperature-sensitive cell growth of the rpoH15 mutant and partially restored heat shock induction in the mutant cell (40). A coldsensitive mutation was also mapped in the suhB locus as an extragenic suppressor for the dnaB121(Ts) mutation that inhibits replication of phage (2). Thus, mutant alleles of suhB have effects on diverse cell activities, including protein export, stress response, and DNA replication.The suhB gene encodes a protein of 268 amino acids (40), and the primary structure of its translated product shows a high level of similarity t...
To clarify the clinical efficacy of STFX for patients with non-gonococcal urethritis (NGU), including chlamydial urethritis and Mycoplasma genitalium-positive urethritis, this study included male patients with NGU who were 20 years old or older. The pathogens, including Chlamydia trachomatis, M. genitalium and Ureaplasma urealyticum, were detected by nucleic acid amplification tests and the patients were treated with sitafloxacin 100 mg twice daily for 7 days. Microbiological and clinical efficacies were assessed for the patients with NGU posttreatment. Among the 208 patients enrolled in this study, data for a total of 118 patients could be analyzed. The median age was 32 (20-61) years. The median duration from the completion of treatment to the second visit was 21 (14-42) days. There were 68 pathogen-positive NGU cases and 50 with NGU without any microbial detection. Microbiological cure was achieved in 95.6% of the pathogen-positive NGU patients. Total clinical cure was achieved in 91.3% (105/115). In this study, STFX was able to eradicate 95.7% of C. trachomatis, 93.8% of M. genitalium and 100% of U. urealyticum. The results of our clinical research indicate that the STFX treatment regimen should become a standard regimen recommended for patients with NGU. In addition, this regimen is recommended for patients with M. genitalium-positive NGU.
The biphenyl-utilizing bacterial strain KBC101 has been newly isolated from soil. Biphenyl-grown cells of KBC101 efficiently degraded di- to nonachlorobiphenyls. The isolate was identified as Paenibacillus sp. with respect to its 16S rDNA sequence and fatty acid profiles, as well as various biological and physiological characteristics. In the case of highly chlorinated biphenyl (polychlorinated biphenyl; PCB) congeners, the degradation activities of this strain were superior to those of the previously reported strong PCB degrader, Rhodococcus sp. RHA1. Recalcitrant coplanar PCBs, such as 3,4,3',4'-CB, were also efficiently degraded by strain KBC101 cells. This is the first report of a representative of the genus Paenibacillus capable of degrading PCBs. In addition to growth on biphenyl, strain KBC101 could grow on dibenzofuran, xanthene, benzophenone, anthrone, phenanthrene, naphthalene, fluorene, fluoranthene, and chrysene as sole sources of carbon and energy. Paenibacillus sp. strain KBC101 presented heterogeneous degradation profiles toward various aromatic compounds.
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