Helicobacter pylori divides in the human stomach resulting in persistent infections and causing various disorders. Bacterial cell division is precisely coordinated by many molecules, including FtsZ and Min proteins. However, the role of Min proteins in H. pylori division is poorly understood. We investigated the functional characteristics of Min proteins in wild-type HPK5 and five HPK5-derivative mutants using morphological and genetic approaches. All mutants showed a filamentous shape. However, the bacterial cell growth and viability of three single-gene mutants (minC, minD, minE) were similar to that of the wild-type. The coccoid form number was lowest in the minE-disruptant, indicating that MinE contributes to the coccoid form conversion during the stationary phase. Immunofluorescence microscopic observations showed that FtsZ was dispersedly distributed throughout the bacterial cell irrespective of nucleoid position in only minD-disruptants, indicating that MinD is involved in the nucleoid occlusion system. A chase assay demonstrated that MinC loss suppressed FtsZ-degradation, indicating that FtsZ degrades in a MinC-dependent manner. Molecular interactions between FtsZ and Min proteins were confirmed by immunoprecipitation (IP)-western blotting (WB), suggesting the functional cooperation of these molecules during bacterial cell division. This study describes the intrinsic characteristics of Min proteins and provides new insights into H. pylori cell division.

Chlorazol Black E (CBE) stain has been used for the detection and identification of intestinal parasitic protozoa. In recent years, genotyping of protozoa has been performed to examine pathogenicity and for epidemiologic analysis. In this study, protozoan DNA was amplified from preserved human fecal specimens stained with CBE that were positive for Giardia intestinalis (syn. G. lamblia and G. duodenalis), Chilomastix mesnili, Pentatrichomonas hominis, and Entamoeba histolytica. DNA was amplified from 11 of the 12 (91.6%) samples examined. DNA from CBE-stained smears of G. intestinalis, E. histolytica, and P. hominis was amplified, whereas any amplification product could not be obtained from one of three smears of C. mesnili. Storage term and protozoan number had no association with results of PCR amplification. In genotyping of G. intestinalis, four out of six (66.7%) samples were of genotype AI, while the remaining two (33.3%) samples were of genotype B. The amplified DNA sequences showed high similarity (>99%) with that of G. intestinalis in the GenBank database. These results suggest that DNA remains stable in CBE-stained smears for long term. The present study demonstrates that nuclear extracts from specimens stained with CBE can be amplified by PCR and suggests that specimens stored for extended periods could be applied to genetic and prospective epidemiologic analyses.

We evaluated the DiversiLab (DL) system with universal primers, a semiautomated repetitive extragenic palindromic sequence-based polymerase chain reaction (PCR) (rep-PCR) system, for the characterization of Helicobacter pylori in Japan. All 135 isolates from Japanese patients with gastric cancer (GC, n = 55) or non-GC (n = 80) were used and subjected to the drug susceptibility examinations (amoxicillin, AMPC; metronidazole, MNZ; and clarithromycin, CAM) by E-test. There were 28 MNZ-resistant (20.7%), 35 CAM-resistant (25.9%), and 16 MNZ/CAM-resistant (11.9%) isolates. DL rep-PCR fingerprinting analysis at the level of 95% similarity revealed five major groups (A-E) and the other including 45 isolates. The occupation rates of GC-derived isolates in groups B (54.2%) and E (58.8%) were higher than in the other groups: A (26.7%), C (28.6%), D (30.0%), and the other (40.0%). Relative higher occupation rates of drug resistants, such as MNZ-, CAM- and double MNZ/CAM-resistant isolates, were observed in groups B (45.8%), C (42.6%), and D (40%). Five of eight GC-derived isolates with MNZ/CAM resistance were significantly assigned to group B (P = 0.0312, χ(2) -test). These results suggest that the isolates classified in group B have a potential to contribute to the development of severe gastric disorders. The DL system, rapid and high sensitive technology, would be widely available in clinical laboratory for pathological and epidemiological analyses even in H. pylori.

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