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F Kawamura

Publications and source records attributed to F Kawamura.

At least 37 records · Page 2Linked to original sources
PubMed1998

A novel sporulation-control gene (spo0M) of Bacillus subtilis with a sigmaH-regulated promoter.

A novel sporulation-control gene (spo0M) of Bacillus subtilis was cloned, sequenced and analyzed. The spo0M gene is located at the end of large tRNA gene clusters including rrnD and codes for a 257-amino-acid protein with a calculated size of 29.6kDa. The protein Spo0M has a strong negative charge (calculated pI=4.3) and shows no significant sequence homology to any known proteins. Gene disruption experiments revealed that spo0M is not essential for cell viability, but its disruption results in considerable impairments (decreasing by 20- to 100-fold) in sporulation. The morphological stage blocked in sporulation was stage 0 as observed by electron microscopy, and expression analysis using spo0Aps-bgaB fusion revealed an impaired gene expression of spo0A in the spo0M mutant. In contrast, spo0M disruption had no effect on antibiotic productivity. Propagation of the spo0M gene in wild-type cells using a high-copy-number plasmid also impaired sporulation, indicating that overproduction of Spo0M exerts certain negative effects on sporulation. spo0M gene expression is controlled by sigmaH, as demonstrated: (1) by monitoring expression of a bgaB transcriptional fusion integrated into the amyE locus on the chromosome of the wild-type or spo0H mutant cells, and (2) by in-vitro transcription of spo0M gene with EsigmaH.

Amino Acid Sequence↗
PubMed1998

ClpC regulates the fate of a sporulation initiation sigma factor, sigmaH protein, in Bacillus subtilis at elevated temperatures.

Using a strain carrying a clpC-bgaB transcriptional fusion at the amyE locus, we found that the expression of a clpC operon was induced at the end of exponential growth in a sigmaB-independent manner and ceased around T3.5 in the wild type but not in a spo0H mutant. This suggests that some gene product(s) whose expression is dependent on sigmaH function is required for the turn-off of clpC transcription during an early stage of sporulation. A clpC deletion mutant showed a temperature-sensitive sporulation phenotype and exhibited an abnormally large accumulation of sigmaH in the cell at 45 degrees C after T2, at which time the sigmaH level in the wild type had begun to decrease. These results, together with the fact that spo0H transcription in the clpC deletion mutant was similar to that of the wild type, suggested that ClpC may be responsible for the degradation of sigmaH after the accomplishment of its role in sporulation. Moreover, as expected from these results, overproduction of Spo0A was also observed after the initiation of sporulation in the clpC deletion mutant at 45 degrees C.

Bacillus subtilis↗
PubMed1998

Restricted transcription from sigma H or phosphorylated spo0A dependent promoters in the temperature-sensitive secA341 mutant of Bacillus subtilis.

The temperature-sensitive secA341 mutation of Bacillus subtilis affects sporulation and sporulation-associated events as well as protein secretion and cell septation. With lacZ or bgaB fusion genes, we examined the expression of the early sporulation genes in the mutant strain. Transcriptional expression of delta H dependent kinA, spo0A (Ps), phrC, spoVG, and citG (p2) genes was blocked by the secA341 mutation at 37 degrees C. On the other hand, neither repression of the abrB gene nor induction of the spoH (delta H) gene was affected. Active RNA polymerase containing delta H was, however, found to be produced in the mutant cells. Expression of the phosphorylated Spo0A dependent spoIIG operon was also blocked. Thus the secA341 mutation blocks some step(s) or factor(s) required for delta H-dependent transcription in vivo.

Adenosine Triphosphatases↗
PubMed1997

Isolation and characterization of a sporulation initiation mutation in the Bacillus subtilis secA gene.

A Bacillus subtilis secA mutant, secA12, which is blocked at an early stage of sporulation, is able to grow as well as the wild-type strain at all temperatures tested. Experiments with lacZ fusion genes showed that the induction of kinA expression, as well as the sporulation-specific transcription of the spo0A gene, was not observed in the secA12 mutant. However, transcription of the spo0H gene (coding for sigmaH, which is required for the transcription of kinA and spo0A) and accumulation of the sigmaH protein were not affected in secA12. These results suggested that mutations in secA affect a factor required for efficient transcription of kinA as well as for the activation of the phosphorelay pathway.

Adenosine Triphosphatases↗
PubMed1997

Suppression of initiation defects of chromosome replication in Bacillus subtilis dnaA and oriC-deleted mutants by integration of a plasmid replicon into the chromosomes.

We constructed Bacillus subtilis strains in which chromosome replication initiates from the minimal replicon of a plasmid isolated from Bacillus natto, independently of oriC. Integration of the replicon in either orientation at the proA locus (115 degrees on the genetic map) suppressed the temperature-sensitive phenotype caused by a mutation in dnaA, a gene required for initiation of replication from oriC. In addition, in a strain with the plasmid replicon integrated into the chromosome, we were able to delete sequences required for oriC function. These strains were viable but had a slower growth rate than the oriC+ strains. Marker frequency analysis revealed that both pyrD and metD, genes close to proA, showed the highest values among the markers (genes) measured, and those of other markers decreased symmetrically with distance from the site of the integration (proA). These results indicated that the integrated plasmid replicon operated as a new and sole origin of chromosome replication in these strains and that the mode of replication was bidirectional. Interestingly, these mutants produced anucleate cells at a high frequency (about 40% in exponential culture), and the distribution of chromosomes in the cells was irregular. A change in the site and mechanism (from oriC to a plasmid system) of initiation appears to have resulted in a drastic alteration in coordination between chromosome replication and chromosome partition or cell division.

Aldehyde Oxidoreductases↗
PubMed1997

Lansoprazole elevates the ratio of serum pepsinogen I v.s. pepsinogen II.

In order to investigate the mechanism by which proton pump inhibitor increases serum pepsinogen levels, we evaluated the effects of ulcer location and IgG antibody against Helicobacter pylori on lansoprazole-induced elevations. Patients with endoscopically proven peptic ulcer received lansoprazole 30 mg/day for 6 or 8 weeks; pepsinogen I and II levels, along with antibody to H. pylori, were measured in fasting blood samples. We found that whether or not antibody to H. pylori was present, pepsinogen I and II levels and the I/II ratio rose significantly in lansoprazole-treated patients. Patients with stomach-body ulcers showed smaller increases in both pepsinogens than did those with ulcers in the gastric angle/antrum or in the duodenum. In conclusion, lansoprazole increases serum levels of both pepsinogens I and II, although a larger increase in pepsinogen I elevates the pepsinogen I/II ratio. The relatively small increases seen in patients with stomach-body ulcers suggest atrophic changes in the gastric mucosa in patients with stomach-body ulcer.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1996

Sequence analysis of a 50 kb region between spo0H and rrnH on the Bacillus subtilis chromosome.

The 49630 bp spo0H-rrnH region of the Bacillus subtilis genome has been fully sequenced. The sequence contains one partial and 62 complete ORFs, one partial and three complete rRNA genes and a cluster of six tRNA genes. The direction of the transcription and translation of 61 ORFs is the same as that of the movement of the replication fork. A homology search of 40 ORFs in newly determined sequence revealed that 27 of them had significant similarity to known proteins such as elongation factor G, elongation factor Tu, pseudouridine synthase I and ribsosomal proteins. Two adjacent genes, ybaD and ybaE, appeared to encode proteins belonging to the ATP-binding cassette (ABC) family.

Bacillus subtilis↗
PubMed1995

Effects of spo0 mutations on spo0A promoter switching at the initiation of sporulation in Bacillus subtilis.

Transcriptional analyses of the Bacillus subtilis sporulation initiator gene spo0A revealed that promoter switching from the vegetative (Pv) to the sporulation-specific (Ps) promoter did not occur in the spo0A, spo0B, spo0E, spo0F, and spo0H mutants. The sof-1 mutation in spo0A restored the promoter switching in the spo0F mutant. These results strongly suggest that Spo0A plays a central role in the regulation of its own promoter switching.

Bacillus subtilis↗
PubMed1995

Expression of kinA and accumulation of sigma H at the onset of sporulation in Bacillus subtilis.

Induction of the Bacillus subtilis kinA gene, which codes for a major kinase of the phosphorelay pathway, required the spo0H gene, coding for the sigma H protein, but not the genes spo0A, spo0B, and spo0F at the onset of sporulation. Also, the levels of sigma H in spo0A, spo0B, and spo0F mutants were increased at the onset of sporulation, though induction of spo0H transcription in all of these mutants was appreciably inhibited. In addition, kinA expression was almost completely eliminated in a medium supplemented with excess glucose and glutamine, even though the usual stationary-phase-associated increase in sigma H was observed under these conditions.

Bacillus subtilis↗
PubMed1993

Temperature-sensitive sporulation caused by a mutation in the Bacillus subtilis secY gene.

A thermosensitive sporulation mutant of Bacillus subtilis containing a mutation in the secY gene was isolated and characterized. No asymmetric septum specific to the sporulation was detected by electron microscopy at the nonpermissive temperature, indicating that the block occurred at a very early stage of sporulation. Furthermore, competence development in the mutant cell was affected even at the sporulation-proficient temperature. It is assumed that the SecY protein of B. subtilis has multiple roles both in the regulation of spore formation and in stationary-phase-associated phenomena.

Bacillus subtilis↗
PubMed1992

Isolation and characterization of the groES and groEL genes of Bacillus subtilis Marburg.

The complete set of groES and groEL gene homologues from Bacillus subtilis Marburg 168 was identified, cloned, and characterized. The nucleotide sequence indicated the presence of two open reading frames corresponding to the groES and groEL genes. The presumptive GroES and GroEL proteins were calculated to be polypeptides of 10,175 and 57,175 Da, respectively, and showed extensive sequence similarities with the known GroES and GroEL proteins of Escherichia coli and Mycobacterium tuberculosis. A heat-inducible transcript initiated upstream of the groES coding region was identified by primer-extension analysis of in vivo transcripts, indicating that the two genes consist of an operon. At least six heat-shock inducible proteins were identified in the cell extract of heat treated B. subtilis. Two proteins of 10 and 60 kDa overproduced in B. subtilis cells carrying a multi-copy groES and groEL plasmid were demonstrated to correspond to two out of the six heat-shock inducible proteins. The groES and groEL genes of B. subtilis were physically mapped on the 60 degrees region of a 360 degrees map and genetically mapped at the position of 40% linkage with the purB locus using PBS1 transduction of the groEL genes tagged with a chloramphenicol resistance (chlr) marker.

Amino Acid Sequence↗
PubMed1992

Molecular cloning.

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Bacillus subtilis↗
PubMed1991

Differential regulation of spo0A transcription in Bacillus subtilis: glucose represses promoter switching at the initiation of sporulation.

We have shown by S1 nuclease mapping with in vivo transcripts that the differential expression of a sporulation-regulatory gene, spo0A, is regulated by switching of two discrete promoters during the initiation of sporulation in Bacillus subtilis; vegetative mRNA was transcribed from an upstream promoter (Pv, vegetative promoter), and sporulation-specific mRNA was transcribed from the other promoter (Ps, sporulation-specific promoter) about 150 bp downstream of the Pv promoter. Transcription from the Pv promoter was at a low level and shut off at T0.5. On the other hand, transcription from the Ps promoter was strongly induced at T0.5 and increased until T2.5. In the presence of 2% glucose, Pv-directed transcription was not shut off and was observed even at T1.5, whereas the induction of Ps-directed transcription was completely repressed. A mutant in which the spo0A gene was transcribed only from the Ps promoter could sporulate normally in the presence of 0.1% glucose but could not sporulate at all in the presence of 2% glucose. In a catabolite-resistant sporulation mutant carrying crsA47 (sigA47), a mutation within the gene encoding sigma A, normal promoter switching from Pv to Ps was observed in the presence of 2% glucose.

Bacillus subtilis↗
PubMed1990

Comparative studies on the usefulness of phosphate versus glycerin enema in preparation for colon examinations.

Fifty of 100 persons who had undergone health screening received phosphate enema while the other 50 received glycerin enema prior to proctoscopy and barium enema, and their usefulness for preparation for colon examination was compared by a double-blind test. There was no significant difference in the degree of colonic cleansing achieved by proctoscopy and barium enema. In the subjects who received phosphate enema, the incidence of abdominal pain was less than that in those who received glycerin enema, while the effect of phosphate enema on defecation appeared later than that of glycerin enema, indicating prolonged stool retention in the subjects given phosphate enema. To study the safety of the two enemas, either phosphate enema, glycerin enema or physiological saline solution as a control was administered at 0.35 ml/animal in the rectum by 4-h closure of the anus in 10 male 7-week-old Wistar rats, and the rectal mucosa was observed for irritation macroscopically and histopathologically. Glycerin enema produced less irritation than phosphate enema diffusely in the entire area of the rectum, while phosphate enema produced more local irritation at the end of the rectum than glycerin enema. The differences in the extent of irritation and injury between phosphate and glycerin enemas were considered to be derived from differences in the pharmacologic actions of these drugs. If the extent of injury were included in the extent of irritation, the difference in irritation between phosphate and glycerin enemas would not be significant. As described above, no specific difference seem to exist in the usefulness of phosphate and glycerin enemas as preparation for colon examination.

Animals↗
PubMed1990

Nursing for a patient requiring long-term care in an intensive care unit (ICU).

Nursing care in ICUs has frequently been discussed, and importance of psychological care for each patient has been recognised. The care of a severely ill patient who remained in the ICU in Japan for an extended time is described here. During his stay in the ICU, an expanded nursing programme was developed to minimise his mental exhaustion. While considering his pathophysiological condition nursing support was also designed to satisfy his basic desires and human needs, anticipating that this would have therapeutic effects and contribute to improvement of his general condition. Nursing care included particular emphasis on four areas of nursing intervention promoting mobility, and communication between the patient and his family and nurses. Exercise, food intake, sleep, and mental condition were carefully evaluated. The basic human desires of the patient (such as to eat, sleep, walk, etc) should be satisfied, taking into account the pathophysiological condition, even with a severely ill patient. Nursing care should focus on supporting the quality of life for patients, even in the ICU.

Aged↗