The scarab beetleAnomala albopilosa sakishimana utilizes the same sex pheromone blend as a closely related and geographically isolated species,Anomala cuprea

Two components were identified in the sex pheromone system of the green chafter,Anomala albopilosa sakishimana Nomura: (R,Z)-5-(-)-(oct-1-enyl)oxacyclopentan-2-one (buibuilactone) and (R,Z)-5-(-)-(dec-1-enyl)oxyacyclopentan-2-one (japonilure), which have been previously identified as sex pheromone constituents ofA. cuprea andA. octiescostata. A female-specific minor component, (R,E)-5-(-)-(oct-1-enyl)oxacyclopentan-2-one, did not seem to be involved in pheromonal communication because it was not EAD active, but its role remained unclear. A synthetic blend of the two components captured significantly more beetles than any other treatments. Nevertheless, the fact that both the synthetic sex pheromone and field-captured female beetles were weak lures convinced us that the sex pheromone system may be only part of a complex communication system, probably involving plant volatiles. Although the sex pheromone was released during both the scotophase and photophase, there was an increase of 60% in the photophase.

Confirmation by DNA analysis that Contarinia maculipennis (Diptera: Cecidomyiidae) is a polyphagous pest of orchids and other unrelated cultivated plants

The cytochrome oxidase subunit I gene in mitochondrial DNA of 53 larvae of Contarinia maculipennis Felt from flower buds of various host plants, collected from Hawaii, Japan and Thailand was analysed. Monophyly of the clade including C. maculipennis from Hawaii, Thailand and Japan was supported. There was no sequential variation within the specimens from Hawaii and Japan, which differed from one another by 6 bp (1.37%). Three haplotypes were recognized in specimens from Thailand but differences from Hawaiian and Japanese specimens were small. Overall, there were no differences in the 146 deduced amino acid residues. It is therefore concluded that C. maculipennis is a polyphagous species that can develop on plant hosts representing at least seven botanical families. This pest of Dendrobium flower buds in glasshouses is considered to have entered Hawaii, Florida and Japan from Southeast Asia, and was recently intercepted in the Netherlands. Infestations have established and spread in orchid glasshouses, causing concern about the possibility of more extensive damage to orchids and to crops, such as bitter gourd, grown in close proximity to orchid glasshouses in Japan. The potential usefulness of DNA analysis in determining host plant ranges of morphologically identical cecidomyiid species that are currently identified solely on differences of host plant is emphasized.

Prevalence of Helicobacter pylori in NSAID users with gastric ulcer

OBJECTIVE

Regarding the interaction of Helicobacter pylori and non-steroidal anti-inflammatory drugs (NSAIDs), we cannot accept unanimous conclusions in inducing gastric ulcer. We therefore evaluated the role of Helicobacter pylori and NSAIDs in inducing gastric ulcer.

METHODS

Dyspeptic patients receiving NSAIDs underwent endoscopic examination. Gastric ulcer formation and H. pylori status were investigated. Biopsy specimens from the antrum and lower body of the stomach were prepared for the rapid urease test and pathological evaluation. Anti-H. pylori antibody was measured by enzyme-linked immunosorbent assay.

RESULTS

Two hundred and twenty-six patients receiving NSAIDs (220 chronic and six on-demand users) underwent gastrofibrescopic examination. There were 110 patients with gastric ulcer and 111 non-ulcer patients with gastritis. The remaining five patients had neither. NSAID users with gastric ulcer showed a low prevalence of H. pylori compared with those without them [55/110 (50.0%) vs 79/111 (71.2%), P < 0.01]. The same tendency was seen when patients receiving low-dose aspirin and those with rheumatoid arthritis were analysed separately [13/29 (44.8%) vs 50/62 (80.6%), P < 0.01, and 11/33 (33.3%) vs 16/26 (61.5%), P < 0.06 with Yates' correction, respectively].

CONCLUSION

Helicobacter pylori infection appeared to be a risk factor for developing gastritis, but we found no evidence that it increases gastric ulcer formation in NSAID users with dyspepsia.

Essential Bacillus subtilis genes

To estimate the minimal gene set required to sustain bacterial life in nutritious conditions, we carried out a systematic inactivation of Bacillus subtilis genes. Among approximately 4,100 genes of the organism, only 192 were shown to be indispensable by this or previous work. Another 79 genes were predicted to be essential. The vast majority of essential genes were categorized in relatively few domains of cell metabolism, with about half involved in information processing, one-fifth involved in the synthesis of cell envelope and the determination of cell shape and division, and one-tenth related to cell energetics. Only 4% of essential genes encode unknown functions. Most essential genes are present throughout a wide range of Bacteria, and almost 70% can also be found in Archaea and Eucarya. However, essential genes related to cell envelope, shape, division, and respiration tend to be lost from bacteria with small genomes. Unexpectedly, most genes involved in the Embden-Meyerhof-Parnas pathway are essential. Identification of unknown and unexpected essential genes opens research avenues to better understanding of processes that sustain bacterial life.

Deficiency of the initiation events of sporulation in Bacillus subtilis clpP mutant can be suppressed by a lack of the Spo0E protein phosphatase

Previous results have shown that the Bacillus subtilis clpP gene is required for developmental processes such as sporulation and competence development. Little is known about its function during the initiation of sporulation. We studied the effect of clpP mutation on the early events of sporulation. The expression of the spo0A and spoIIG genes, whose active transcription requires the phosphorylated Spo0A protein (Spo0A approximately P) as the transcription activator, was significantly decreased in the clpP mutant at the onset of sporulation. The expression of spo0H gene encoding sigma(H) protein was also greatly reduced. As expected from these results, the sigma(H) and Spo0A protein levels in the clpP mutant were also decreased during the initiation of sporulation, indicating that the accumulation of Spo0A approximately P was inhibited in the clpP mutant. We, therefore, introduced the mutation of the spo0E gene, which codes for the Spo0A approximately P-specific phosphatase, into the clpP mutant and found that this double mutant restored the expression of the spo0A as well as spoIIG genes. These results suggest that ClpP had an indirect influence on the intracellular concentration of Spo0A approximately P by regulating the activity of the Spo0E phosphatase during the initiation of sporulation.

Suppression of temperature-sensitive sporulation mutation in the Bacillus subtilis sigA gene by rpoB mutation

We isolated a temperature-sensitive sporulation defective mutant of the sigA gene, encoding a major sigma factor, sigma(A) protein, in Bacillus subtilis, and designated it as sigA21. The sigA21 mutation caused a single-amino acid substitution, E314K, in region 4 of the sigma(A) protein. In this mutant, expression of the spoIIG gene, whose transcription depends on both sigma(A) and the phosphorylated Spo0A protein, Spo0A approximately P, a major transcription factor during early stages of sporulation, was greatly reduced at 43 degrees C. To obtain further information on the mechanism of sigma(A) function during the early spore development, we isolated a spontaneous sporulation-proficient suppressor mutant at 43 degrees C. This extragenic suppressor mutation was mapped within the rpoB gene, encoding the beta subunit of RNA polymerase, and was found to have a single-amino acid substitution, A863G. In this mutant, the expression of the spoIIG is partially restored at 43 degrees C.

Lignans causing photodiscoloration of Tsuga heterophylla: 8-hydroxy-oxomatairesinol from sapwood

A lignan, (8S,8'S,)-(+)-8-hydroxy-oxomatairesinol, has been isolated from the sapwood of Tsuga heterophylla (western hemlock, Pinaceae). The known lignans matairesinol, lariciresinol and secoisolariciresinol were also obtained. The structure of the compound was established by 1D and 2D NMR spectroscopy. Results of the light-irradiation test of the lignans from T. heterophylla are also reported.

Natural genetic competence in Bacillus subtilis natto OK2

We isolated a Bacillus subtilis natto strain, designated OK2, from a lot of commercial fermented soybean natto and studied its ability to undergo natural competence development using a comG-lacZ fusion at the amyE locus. Although transcription of the late competence genes was not detected in the B. subtilis natto strain OK2 during competence development, these genes were constitutively transcribed in the OK2 strain carrying either the mecA or the clpC mutation derived from B. subtilis 168. In addition, both OK2 mutants exhibited high transformation frequencies, comparable with that observed for B. subtilis 168. Moreover, as expected from these results, overproduction of ComK derived from strain 168 in strain OK2 resulted in a high transformation frequency as well as in induction of the late competence genes. These results clearly indicated that ComK produced in both the mecA and clpC mutants of strain OK2 (ComK(OK2)) could activate the transcription of the whole set of late competence genes and suggested that ComK(OK2) was not activated in strain OK2 during competence development. We therefore sequenced the comS gene of OK2 and compared it with that of 168. The comS(OK2) had a single-base change, resulting in the replacement of Ser (strain 168) by Cys (strain OK2) at position 11.

Genetic analysis of SecA-SecY interaction required for spore development in Bacillus subtilis

All spontaneous suppressor mutations obtained from a secA12 sporulation-defective mutant in Bacillus subtilis were localized in highly conserved membrane-spanning regions of SecY. The expression of early sporulation genes, kinA and spo0A encoding a histidine kinase and a transcription regulator for several sporulation genes, respectively, was restored in these suppressor mutants. These results indicate that the secretion function of translocase combined with Sec proteins is required for sporulation in B. subtilis.

Function of a principal Na(+)/H(+) antiporter, ShaA, is required for initiation of sporulation in Bacillus subtilis

ShaA (sodium/hydrogen antiporter, previously termed YufT [or NtrA]), which is responsible for Na(+)/H(+) antiporter activity, is considered to be the major Na(+) excretion system in Bacillus subtilis. We found that a shaA-disrupted mutant of B. subtilis shows impaired sporulation but normal vegetative growth when the external Na(+) concentration was increased in a low range. In the shaA mutant, sigma(H)-dependent expression of spo0A (P(S)) and spoVG at an early stage of sporulation was sensitive to external NaCl. The level of sigma(H) protein was reduced by the addition of NaCl, while the expression of spo0H, which encodes sigma(H), was little affected, indicating that posttranscriptional control of sigma(H) rather than spo0H transcription is affected by the addition of NaCl in the shaA mutant. Since this mutant is considered to have a diminished ability to maintain a low internal Na(+) concentration, an increased level of internal Na(+) may affect posttranscriptional control of sigma(H). Bypassing the phosphorelay by introducing the sof-1 mutation into this mutant did not restore spo0A (P(S)) expression, suggesting that disruption of shaA affects sigma(H) accumulation, but does not interfere with the phosphorylation and phosphotransfer reactions of the phosphorelay. These results suggest that ShaA plays a significant role at an early stage of sporulation and not only during vegetative growth. Our findings raise the possibility that fine control of cytoplasmic ion levels, including control of the internal Na(+) concentration, may be important for the progression of the sporulation process.

[A case of water intoxication during transcervical resection of the uterine myoma]

A 28-year-old woman underwent trans-cervical resection (TCR) of the uterine myoma. She had no history of complications except for anemia. Anesthesia was maintained with inhalation anesthesia. After 120 min from introducing the resectoscope, her serum sodium dropped to 86.1 mEq.l-1. But her heart rate and the systolic arterial pressure were stable. She was treated with steroid, mannitol, isotonic saline, and 7% NaHCO3. Soon after the end of the operation, she recovered consciousness. At two hours postoperatively, her serum sodium was 119.6 mEq.l-1. On the 1st postoperative day, her serum sodium returned to the normal range (137 mEq.l-1). We should be aware of asymptomatic water intoxication during TCR.

Thermo-labile stability of sigmaH (Spo0H) in temperature-sensitive spo0H mutants of Bacillus subtilis can be suppressed by mutations in RNA polymerase beta subunit

We isolated novel temperature-sensitive mutants of spo0H, spo0H1 and spo0H5, having E61K and G30E amino-acid substitutions within the sigmaH protein, respectively, and located in the highly conserved region, "2", among prokaryotic sigma factors that participates in binding to core enzyme of RNA polymerase. These mutants showed a sporulation-deficient phenotype at 43 degrees C. Moreover, we successfully isolated suppressor mutants that were spontaneously generated from the spo0H mutants. Our genetic analysis of these suppressor mutations revealed that the suppressor mutations are within the rpoB gene coding for the beta subunit of RNA polymerase. The mutations caused single amino-acid substitutions, E857A and P1055S, in rpoB18 and rpoB532 mutants that were generated from spo0H1 and spo0H5, respectively. Whereas the sigmaH-dependent expression of a spo0A-bgaB fusion was greatly reduced in both spo0H mutants, their expression was partially restored in the suppressor mutants at 43 degrees C. Western blot analysis showed that the level of sigmaH protein in the wild type increased between T0 and T2 and decreased after T3, while the level of sigmaH protein in spo0H mutants was greatly reduced throughout growth, indicating that the mutant sigmaH proteins were rapidly degraded by some unknown proteolytic enzyme(s). The analysis of the half-life of sigmaH protein showed that the short life of sigmaH in spo0H mutants is prolonged in the suppressor mutants. These findings suggest that, at least to some extent, the process of E-sigmaH formation may be involved in stabilization of sigmaH at the onset of sporulation.

Cloning of oxetanocin A biosynthetic and resistance genes that reside on a plasmid of Bacillus megaterium strain NK84-0128

Bacillus megaterium strain NK84-0218 produces a potent antiviral antibiotic, oxetanocin A, which has an oxetanosyl-N-glycoside linkage to an adenine moiety. However, the oxetanocin A productivity of the original strain was unstable and low. In this study, oxetanocin A productivity and resistance was shown to be lost simultaneously when a 51.5-kb plasmid, pOXT1, was cured during cultivation. The deficiency of oxetanocin A productivity and resistance was restored by re-introduction of the pOXT1 plasmid into the cured strain. By a cloning experiment it was shown that a 6.8-kb BglI-D fragment of the pOXT1 plasmid was responsible for oxetanocin A productivity and resistance.

The lethal effect of a benzamide derivative, 3-methoxybenzamide, can be suppressed by mutations within a cell division gene, ftsZ, in Bacillus subtilis

3-Methoxybenzamide (3-MBA), which is known to be an inhibitor of ADP-ribosyltransferase, inhibits cell division in Bacillus subtilis, leading to filamentation and eventually lysis of cells. Our genetic analysis of 3-MBA-resistant mutants indicated that the primary target of the drug is the cell division system involving FtsZ function during both vegetative growth and sporulation.

Accelerated solvent extraction of paclitaxel and related compounds from the bark of taxus cuspidata

Accelerated solvent extraction (ASE) of paclitaxel and related compounds from Taxus cuspidata (Japanese yew) bark has been investigated under various conditions. In ASE, pressure is applied to the sample extraction cell to maintain the heated solvent in a liquid state during the extraction. This method is able to shorten the extraction time and to increase the recovery of target compounds. In this study, ASE of paclitaxel, baccatin III, and 10-deacetylbaccatin III produced amounts of these compounds that were higher than those from ordinary solvent extraction at room temperature. The conditions providing the highest recovery of paclitaxel were as follows: solvent, MeOH-H2O (90:10); temperature, 150 degrees C; and pressure, 10.13 MPa (0.128% w/w recovery based on oven-dried sample powder). ASE does not require chlorinated solvents and can reduce solvent consumption because of its strong dissolving power. Moreover, with water alone, the recovery of paclitaxel and related compounds using ASE is much higher than with other extraction methods.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

[Investigation of a patient with difficult endotracheal intubation]

Unusually difficult endotracheal intubation was encountered during anesthetic induction of a 41-year-old male, necessitating use of a bronchofiberscope. The usual pre-operative analysis had shown no problems, such as tracheal tumor or stricture. Due to difficult intubation, post-operative evaluations were made and no abnormalities were found. However, investigation of the lateral roentgenogram showed a much greater than average backward bend in the patient's trachea under the vocal cord. It is likely that the sharp bend of the trachea was responsible for difficult intubation.

Dissection of the expression signals of the spoA gene of Bacillus subtilis: glucose represses sporulation-specific expression

The expression of the spo0A-lacZ fusion gene was partially repressed in the presence of an excess of glucose. Expression was restored either by the mutation sigA47(crsA47) or by addition of decoyinine, an inhibitor of GMP synthetase, to the medium. By constructing a lacZ fusion with a smaller fragment of the spo)A gene, we observed a beta-galactosidase profile in which expression was completely repressed by an excess of glucose. This expression was restored by the addition of decoyinine. These results indicate that the expression of the spo0A gene is regulated by at least two different mechanisms, one sensitive to glucose, the other not. Furthermore, the glucose-sensitive regulation was shown to reside at the transcriptional level. It is likely that the reduced expression of the spo0A gene in the presence of glucose at an early stage of sporulation causes the repression of sporulation.

New suppressor mutation sur0B of spo0B and spo0F mutations in Bacillus subtilis

Two extragenic suppressor mutations, sur0B20 and sur0F1, which restore the sporulation of spo0B or spo0F mutants of Bacillus subtilis to the wild-type level, were obtained. These suppressor mutations were located in the spo0A gene. Their location is close to that of the sof-1 mutation, which suppresses spo0B, spo0E and spo0F mutations. However, spo0 strains bearing the sur0B20 mutation differed in several phenotypic characteristics from spo0 mutants bearing the sof-1 suppressor. Nucleotide sequence analysis revealed that the sur0B20 and sur0F1 mutations resulted in Glu14 to Val and Asn12 to Lys conversion, respectively, in the spo0A gene. This result indicates that sur0B20 is a new suppressor of spo0b and spo0F mutations, whereas sur0F1 is identical to sof-1.

Use of the Bacillus subtilis subtilisin signal peptide for efficient secretion of TEM beta-lactamase during growth

We report the development of an efficient Bacillus subtilis secretory system, with the secreted product stably maintained in the medium for 100 h. The system is based on characterization of the subtilisin signal peptidase cleavage site and promoters, catabolite repression of sporulation, presence of a vegetative secreting mechanism, and availability of a protease-deficient strain.

The effect of spo0 mutations on the expression of spo0A- and spo0F-lacZ fusions

We have constructed spo0A-lacZ and spo0F-lacZ fusions with a temperate phage vector and have investigated how spo0 gene products are involved in the expression of each of these genes. The expression of spo0A-lacZ and spo0F-lacZ was stimulated at about the time of cessation of vegetative growth in Spo+ cells. This stimulation of spo0A-lacZ was impaired by mutations in the spo0B, D, E, F or H genes but was not affected by mutations in the spo0J or K genes. Similar results were obtained with the spo0F-lacZ fusion. The effect of the spo0A mutation on spo0A-lacZ expression was characteristic: the spo0A-directed beta-galactosidase activity found during vegetative growth was significantly enhanced in the spo0A mutant. This result suggests that spo0A gene expression is auto-regulated being repressed by its own gene product. Another remarkable observation was the effect of the sof-1 mutation, which is known to be a spo0A allele; it suppressed the sporulation deficiency of spo0B, spo0D and spo0F mutants. The spo0A-lacZ stimulation, which is impaired by any one of these spo0 mutations, was restored by the additional sof-1 mutation.

Revised assignment for the Bacillus subtilis spo0F gene and its homology with spo0A and with two Escherichia coli genes

The nucleotide sequences of spo0F mutant genes which block the early sporulation process of Bacillus subtilis were determined. The mutation sites together with the results of complementation tests suggested that an open reading frame for a polypeptide of Mr = 14,229 is the spo0F gene. The deduced amino acid sequence shows striking homology with that of the spo0A gene. In addition, the upstream region involving the rib some binding site of the spo0F coding region is also similar to those of spo0A and spo0B. These homologies suggest that all three genes have a similar function in regulating the initiation of sporulation, and that their expression is controlled by a common mechanism. Clear homology is also seen between the spo0 gene products and the transcriptional control proteins, OmpR and Dye, of Escherichia coli suggesting that the spo0 gene products also are involved in the control of transcription.

Catabolite-resistant sporulation (crsA) mutations in the Bacillus subtilis RNA polymerase sigma 43 gene (rpoD) can suppress and be suppressed by mutations in spo0 genes

The catabolite-resistant sporulation (crsA) mutation is able to overcome the repressive effect of glucose on sporulation in Bacillus subtilis. Three chromosomal crsA mutations, crsA1, crsA4, and crsA47, were transferred by the "gene conversion" process to B. subtilis plasmid pRPD11, which consists of the entire wild-type rpoD coding sequence, encoding the major sigma 43 factor of B. subtilis RNA polymerase, and pUB110. By DNA sequence analysis we showed that all three crsA mutations were identical two-base changes, CCT (proline) to TTT (phenylalanine), within the rpoD coding sequence. Furthermore, the crsA47 mutation restored spo0J and spo0K sporulation to wild-type levels and partially improved the sporulation efficiencies of spo0B, spo0D, and spo0F. Extragenic suppressors (scr) of crsA47 included mutations in spo0A, spo0D, spo0F, and spo0K plus other mutations that have not been specifically identified. Thus sigma 43 appears to be involved in catabolite repression by glucose, to interact either directly or indirectly with spo0 gene products, and to play an important role in the initiation of spore development in B. subtilis.

Translational coupling in Bacillus subtilis of a heterologous Bacillus subtilis-Escherichia coli gene fusion

Translational coupling was demonstrated in a gene fusion in which the promoter and the N-terminal region of the Bacillus subtilis subtilisin (aprA) gene were fused to a promoterless Tn9-derived chloramphenicol acetyltransferase (CAT; EC 2.3.1.28) gene. Expression of this gene fusion results in the production of a native-sized CAT product, whereas the Tn9-derived CAT gene is usually not translated from its own ribosome binding site in B. subtilis (D. S. Goldfarb, R. L. Rodriguez, and R. H. Doi, Proc. Natl. Acad. Sci. USA 79:5886-5890, 1982). A 178-base-pair deletion, which removed part of the signal peptide and the propeptide of the aprA gene and created a translational stop codon 230 base pairs upstream of the CAT gene ribosome binding site, reduced expression of the CAT gene. A BamHI 10-mer linker insertion into this deletion site, which restored the reading frame and simultaneously removed the translation stop codon, restored CAT gene expression. The data indicate that expression of the CAT gene was dependent on translation of the truncated aprA gene into the ribosome binding site of the CAT gene.

Construction of a Bacillus subtilis double mutant deficient in extracellular alkaline and neutral proteases

A mutant strain of Bacillus subtilis carrying lesions in the structural genes for extracellular neutral (nprE) and serine (aprA) proteases was constructed by the gene conversion technique. This mutant had less than 4% of the extracellular protease activity of the wild type and sporulated normally, indicating that neither of these sporulation-associated proteases is essential for development.