One of two osmC homologs in Bacillus subtilis is part of the sigmaB-dependent general stress regulon

In this report we present the identification and analysis of two Bacillus subtilis genes, yklA and ykzA, which are homologous to the partially RpoS-controlled osmC gene from Escherichia coli. The yklA gene is expressed at higher levels in minimal medium than in rich medium and is driven by a putative vegetative promoter. Expression of ykzA is not medium dependent but increases dramatically when cells are exposed to stress and starvation. This stress-induced increase in ykzA expression is absolutely dependent on the alternative sigma factor sigmaB, which controls a large stationary-phase and stress regulon. ykzA is therefore another example of a gene common to the RpoS and sigmaB stress regulons of E. coli and B. subtilis, respectively. The composite complex expression pattern of the two B. subtilis genes is very similar to the expression profile of osmC in E. coli.

Nonnative proteins induce expression of the Bacillus subtilis CIRCE regulon

The chaperone-encoding groESL and dnaK operons constitute the CIRCE regulon of Bacillus subtilis. Both operons are under negative control of the repressor protein HrcA, which interacts with the CIRCE operator and whose activity is modulated by the GroESL chaperone machine. In this report, we demonstrate that induction of the CIRCE regulon can also be accomplished by ethanol stress and puromycin. Introduction of the hrcA gene and a transcriptional fusion under the control of the CIRCE operator into Escherichia coli allowed induction of this fusion by heat shock, ethanol stress, and overproduction of GroESL substrates. The expression level of this hrcA-bgaB fusion inversely correlated with the amount of GroE machinery present in the cells. Therefore, all inducing conditions seem to lead to induction via titration of the GroE chaperonins by the increased level of nonnative proteins formed. Puromycin treatment failed to induce the sigmaB-dependent general stress regulon, indicating that nonnative proteins in general do not trigger this response. Reconstitution of HrcA-dependent heat shock regulation of B. subtilis in E. coli and complementation of E. coli groESL mutants by B. subtilis groESL indicate that the GroE chaperonin systems of the two bacterial species are functionally exchangeable.

Thioredoxin is an essential protein induced by multiple stresses in Bacillus subtilis

Thioredoxin, a small, ubiquitous protein which participates in redox reactions through the reversible oxidation of its active center dithiol to a disulfide, is an essential protein in Bacillus subtilis. A variety of stresses, including heat or salt stress or ethanol treatment, strongly enhanced the synthesis of thioredoxin in B. subtilis. The stress induction of the monocistronic trxA gene encoding thioredoxin occurs at two promoters. The general stress sigma factor, sigmaB, was required for the initiation of transcription at the upstream site, S(B), and the promoter preceding the downstream start site, S(A), was presumably recognized by the vegetative sigma factor, sigmaA. In contrast to the heat-inducible, sigmaA-dependent promoters preceding the chaperone-encoding operons groESL and dnaK, no CIRCE (for controlling inverted repeat of chaperone expression) was present in the vicinity of the start site, S(A). The induction patterns of the promoters differed, with the upstream promoter displaying the typical stress induction of sigmaB-dependent promoters. Transcription initiating at S(A), but not at S(B), was also induced after treatment with hydrogen peroxide or puromycin. Such a double control of stress induction at two different promoters seems to be typical of a subgroup of class III heat shock genes of B. subtilis, like clpC, and it either allows the cells to raise the level of the antioxidant thioredoxin after oxidative stress or allows stressed cells to accumulate thioredoxin. These increased levels of thioredoxin might help stressed B. subtilis cells to maintain the native and reduced state of cellular proteins.

First steps from a two-dimensional protein index towards a response-regulation map for Bacillus subtilis

Data on the identification of proteins of Bacillus subtilis on two-dimensional (2-D) gels as well as their regulation are summarized and the identification of 56 protein spots is included. The pattern of proteins synthesized in Bacillus subtilis during exponential growth, during starvation for glucose or phosphate, or after the imposition of stresses like heat shock, salt- and ethanol stress as well as oxidative stress was analyzed. N-terminal sequencing of protein spots allowed the identification of 93 proteins on 2-D gels, which are required for the synthesis of amino acids and nucleotides, the generation of ATP, for glycolyses, the pentose phosphate cycle, the citric acid cycle as well as for adaptation to a variety of stress conditions. A computer-aided analysis of the 2-D gels was used to monitor the synthesis profile of more than 130 protein spots. Proteins performing housekeeping functions during exponential growth displayed a reduced synthesis rate during stress and starvation, whereas spots induced during stress and starvation were classified as specific stress proteins induced by a single stimulus or a group of related stimuli, or as general stress proteins induced by a variety of entirely different stimuli. The analysis of mutants in global regulators was initiated in order to establish a response regulation map for B. subtilis. These investigations demonstrated that the alternative sigma factor sigma B is involved in the regulation of almost all of the general stress proteins and that the phoPR two-component system is required for the induction of a large part but not all of the proteins induced by phosphate starvation.

Heat-shock and general stress response in Bacillus subtilis

The induction of stress proteins is an important component of the adaptional network of a non-growing cell of Bacillus subtilis. A diverse range of stresses such as heat shock, salt stress, ethanol, starvation for oxygen or nutrients etc. induce the same set of proteins, called general stress proteins. Although the adaptive functions of these proteins are largely unknown, they are proposed to provide general and rather non-specific protection of the cell under these adverse conditions. In addition to these non-specific general stress proteins, all extracellular signals induce a set of specific stress proteins that may confer specific protection against a particular stress factor. In B. subtilis at least three different classes of heat-inducible genes can be defined by their common regulatory characteristics: Class I genes, as exemplified by the dnaK and groE operons, are most efficiently induced by heat stress. Their expression involves a sigma A-dependent promoter, an inverted repeat (called the CIRCE element) highly conserved among eubacteria, and probably a repressor interacting with the CIRCE element. The majority of general stress genes (class II, more than 40) are induced at sigma B-dependent promoters by different growth-inhibiting conditions. The activation of sigma B by stress or starvation is the crucial event in the induction of this large stress regulon. Only a few genes, including Ion, clpC, clpP, and ftsH, can respond to different stress factors independently of sigma B or CIRCE (class III). Stress induction of these genes occurs at promoters presumably recognized by sigma A and probably involves additional regulatory elements which remain to be defined.

sigma B-dependent regulation of gsiB in response to multiple stimuli in Bacillus subtilis

The expression of the gsiB gene of Bacillus subtilis in response to a wide variety of stress conditions was analysed, and the results provide evidence that gsiB is subject to a sigma B-dependent regulation. Primer extension experiments established identical start points for gsiB transcription during growth and after the induction by heat shock, salt or ethanol stress, and glucose limitation. The sequence upstream of the transcription start point shows great similarity to the sequences of sigma B-dependent promoters of B. subtilis. sigma B was absolutely required for the increase in gsiB mRNA level and in the synthesis rate of GsiB in response to various stimuli. Measurements of the ATP pool indicated that changes in the level of ATP might be one of the signals that regulate the activity of sigma B in B. subtilis.

Cloning, nucleotide sequence, and expression of the Bacillus subtilis lon gene

The lon gene of Escherichia coli encodes the ATP-dependent serine protease La and belongs to the family of sigma 32-dependent heat shock genes. In this paper, we report the cloning and characterization of the lon gene from the gram-positive bacterium Bacillus subtilis. The nucleotide sequence of the lon locus, which is localized upstream of the hemAXCDBL operon, was determined. The lon gene codes for an 87-kDa protein consisting of 774 amino acid residues. A comparison of the deduced amino acid sequence with previously described lon gene products from E. coli, Bacillus brevis, and Myxococcus xanthus revealed strong homologies among all known bacterial Lon proteins. Like the E. coli lon gene, the B. subtilis lon gene is induced by heat shock. Furthermore, the amount of lon-specific mRNA is increased after salt, ethanol, and oxidative stress as well as after treatment with puromycin. The potential promoter region does not show similarities to promoters recognized by sigma 32 of E. coli but contains sequences which resemble promoters recognized by the vegetative RNA polymerase E sigma A of B. subtilis. A second gene designated orfX is suggested to be transcribed together with lon and encodes a protein with 195 amino acid residues and a calculated molecular weight of 22,000.

Stress induction of clpC in Bacillus subtilis and its involvement in stress tolerance

A member of the clpC subfamily of stress response-related Clp ATPases was cloned from Bacillus subtilis. The B. subtilis clpC gene was induced in response to various stresses, including heat shock. Its product was identified as a general stress protein (Gsp12) described previously. A dramatic increase in the amount of clpC mRNA immediately after exposure to multiple stresses suggested regulation on a transcriptional level. Induction by heat shock was independent of the alternative sigma factor SigB, indicating a new mechanism of heat shock induction in B. subtilis. A clpC insertional mutant had an impaired tolerance for heat shock and salt stress. Furthermore, the mutation triggered the formation of elongated cells, a phenomenon particularly pronounced during stress.

Analysis of the induction of general stress proteins of Bacillus subtilis

In Bacillus subtilis stress proteins are induced in response to different environmental conditions such as heat shock, salt stress, glucose and oxygen limitation or oxidative stress. These stress proteins have been previously grouped into general stress proteins (Gsps) and heat-specific stress proteins (Hsps). In this investigation the N-terminal sequences of 13 stress proteins of B. subtilis were determined. The quantification of the mRNA and the analysis of the protein synthesis pattern support the initial hypothesis that the chaperones DnaK and GroEL are Hsps in B. subtilis. In contrast, the recently described proteins GsiB, Ctc and RsbW belong to a class of Gsps that are induced by various stresses including heat shock. The main part of the Gsps described in this study failed to be induced in the sigB deletion mutant ML6 in response to heat shock. However, all the five Hsps were induced in this mutant in response to heat shock. These data indicate that SigB plays a crucial role in the induction of general stress genes, but is dispensable for the induction of Hsps.

[Tumor in tumore: breast cancer metastasis in a meningioma]

A 60-year-old woman had undergone surgery for ductal breast carcinoma. Six years after operation there was no local recurrence, but metastases were found in the liver, lungs and in a meningioma.

[An unusual cause of myocardial infarct. Bacterial mitral valve endocarditis, valve ring and myocardial abscess with direct coronary lesion]

We report on a 45-year-old man with bacterial mitral valve endocarditis and valve-ring abscess following a staphylococcus aureus sepsis with septic shock and respiratory insufficiency. A thrombosis of the marginal branch of the left circumflex coronary artery with a myocardial infarction occurred as a consequence of the unusual location of the abscess which spread to the left ventricular lateral wall with an encasement of this blood vessel, and with destruction of the arterial wall. The patient died of biventricular heart failure because of septic shock and myocardial infarction. We discuss entrance spots of infection, predisposing diseases, and complications of valve-ring and myocardial abscesses.

Stress proteins and cross-protection by heat shock and salt stress in Bacillus subtilis

Bacillus subtilis induced a set of general stress proteins in response to a salt or heat stress. Cells subjected to a mild heat stress showed a protective response which enabled them to survive otherwise lethal temperatures (e.g. 52 degrees C). In a similar way bacteria were enabled to survive toxic concentrations of NaCl by pretreatment with lower salt concentrations. A mild heat shock induced a cross-protection against lethal salt stress. The pretreatment of cells with low salt, however, was less effective in the induction of thermotolerance than a preceding mild heat stress. Three stress proteins were identified on the basis of their N-terminal amino acid sequences as homologues of GroEL, DnaK and ClpP of Escherichia coli. The role of general and specific stress proteins in the induction of thermotolerance/salt tolerance and cross-protection is discussed.

Cloning and characterization of heat-inducible promoters of Bacillus subtilis

Heat-inducible DNA fragments of Bacillus subtilis were cloned with two different promoter probe vectors. The increased synthesis of the reporter enzymes seemed to be due to a transient increase in the transcription of the encoding genes. The structure of the heat-sensitive promoters resembles the consensus sequence of promoters recognized by the vegetative form of RNA polymerase of B. subtilis. Our results support data in literature that the heat shock response of B. subtilis is regulated by a different mechanism than in Escherichia coli, where alternative sigma factors direct the transcription of heat shock genes.

Comparative plasma disposition and anticoagulant activities of racemic phenprocoumon and its metabolites in rats

The anticoagulant phenprocoumon (PH) and its metabolites 6-hydroxy-, 7-hydroxy- and 4'hydroxy-phenprocoumon (6-OH-PH, 7-OH-PH and 4'-OH-PH, respectively) were separately administered intravenously as racemates to rats in order to measure the potential effects of the major metabolites of PH on coagulation. Plasma samples were assayed for total concentrations of the administered compounds and the corresponding prothrombin times; kinetic parameters and anticoagulant activities were estimated using a pharmacodynamic model based on the rate of synthesis of clotting factors. The relative potencies were in the order PH > 4'-OH-PH > 6-OH-PH > 7-OH-PH the latter showing no activity. Patients on PH therapy showed lower plasma concentrations of metabolites than of PH; in humans the metabolites of PH will not contribute significantly to the overall anticoagulant activity of the drug.

Cloning, sequencing, mapping, and transcriptional analysis of the groESL operon from Bacillus subtilis

Using a gene probe of the Escherichia coli groEL gene, a 1.8-kb HindIII fragment of chromosomal DNA of Bacillus subtilis was cloned. Upstream sequences were isolated as a 3-kb PstI fragment. Sequencing of 2,525 bp revealed two open reading frames in the order groES groEL. Alignment of the GroES and GroEL proteins with those of eight other eubacteria revealed 50 to 65% and 72 to 84% sequence similarity, respectively. Primer extension studies revealed one potential transcription start site preceding the groESL operon (S) which was activated upon temperature upshift. Northern (RNA) analysis led to the detection of two mRNA species of 2.2 and 1.5 kb. RNA dot blot experiments revealed an at least 10-fold increase in the amount of specific mRNA from 0 to 5 min postinduction, remaining at this high level for 10 min and then decreasing. A 9-bp inverted repeat within the 5' leader region of the mRNA might be involved in regulation of the heat shock response. By using PBS1 transduction, the groESL operon was mapped at about 342 degrees.

Cloning, sequencing, and molecular analysis of the dnaK locus from Bacillus subtilis

By using an internal part of the dnaK gene from Bacillus megaterium as a probe, a 5.2-kb HindIII fragment of chromosomal DNA of Bacillus subtilis was cloned. Downstream sequences were isolated by in vivo chromosome walking. Sequencing of 5,085 bp revealed four open reading frames in the order orf39-grpE-dnaK-dnaJ. orf39 encodes a 39-kDa polypeptide of unknown biological function with no noticeable homology to any other protein within the data bases. Alignment of the GrpE protein with those of three other bacterial species revealed a low overall homology, but a higher homology restricted to two regions which might be involved in interactions with other proteins. Alignment of the DnaK protein with six bacterial DnaK polypeptides revealed that a contiguous region of 24 amino acids is absent from the DnaK proteins of all known gram-positive species. Primer extension studies revealed three potential transcription start sites, two preceding orf39 (S1 and S2) and a third one in front of grpE (S3). S2 and S3 were activated at a high temperature. Northern (RNA) analysis led to the detection of three mRNA species of 4.9, 2.6, and 1.5 kb. RNA dot blot experiments revealed an at-least-fivefold increase in the amount of specific mRNA from 0 to 5 min postinduction and then a rapid decrease. A transcriptional fusion between dnaK and the amyL reporter gene exhibited a slight increase in alpha-amylase activity after heat induction. A 9-bp inverted repeat was detected in front of the coding region of orf39. This inverted repeat is present in a number of other heat shock operons in other microorganisms ranging from cyanobacteria to mycobacteria. The biological property of this inverted repeat as a putative key element in the induction of heat shock genes is discussed. The dnaK locus was mapped at about 223 degrees on the B. subtilis genetic map.

[The effect of biomaterials and other industrial materials on the growth of several aerobic bacterial species in vitro]

The article deals with interactions between bio-vitro-materials and bacteria species in vitro. The growth of S. aureus, Sc. salivarius, E. coli and Ps. aeruginosa in a salt solution with and without addition of biomaterials was examined until the day 60 in a static culture. By counting the cfu/ml and determination the relative change of germ capacity the results were compared. The data of such series obtained with working materials of similar chemical composition were collected and evaluated. We found, that Ps. aeruginosa was promoted in growth by all materials, especially those, which contained carbon. The same can be said about the last materials and E. coli. In contrast as well Ca- and P-containing as--free biomaterials reduced the numbers of germs. Changes of multiplying of S. aureus and Sc. salivarius seldom were observed. It ist apparent, that the biomaterials tested are not indifferent against a few germs, which may cause infections, but they promote the growth of a few species in vitro. This may favour an infection, if such materials should be implanted. It is proposed to test biomaterials microbiologically before clinical application. Materials with indifferent behavior or low anti-microbiological effect have to be favoured.

Excretion into the culture medium of a Bacillus beta-glucanase after overproduction in Escherichia coli

The beta-glucanase gene (bgl) from Bacillus amyloliquefaciens was expressed in E. coli CSH 55 under the control of the PR promoter of phage lambda that is repressed by the thermosensitive repressor C1857. Production of beta-glucanase was drastically stimulated by a temperature shift to 42 degrees C. This overexpression of the bgl gene (about 20% of the total cellular protein) led to an almost complete excretion of the otherwise periplasmic protein into the extracellular medium, beta-glucanase accounted for more than 50% of the extracellular proteins. Col E 1 related plasmid (pEG 1) are amplified in E. coli relA strains in response to an amino acid limitation leading to a 10-fold increase in the activity of plasmid encoded genes. In this work we intended to maximize the expression of the bgl gene by a concerted action of a plasmid amplification and temperature induction. Surprisingly we could not increase the beta-glucanase production above the level reached by plasmid amplification or temperature induction alone. The reasons for this unexpected result will be discussed. Under all conditions tested the expression of the bgl gene was much lower in the E. coli relA strain NF 162 than in E. coli CSH 55; the low beta-glucanase production was accompanied by a reduced excretion rate of the enzyme.

Separation of the enantiomers of phenprocoumon and warfarin by high-performance liquid chromatography using a chiral stationary phase. Determination of the enantiomeric ratio of phenprocoumon in human plasma and urine

The enantiomers of the chiral coumarin-type anticoagulants phenprocoumon, warfarin and p-chlorophenprocoumon were separated by high-performance liquid chromatography on a chiral stationary phase (Nucleosil-Chiral 2) and normal-phase conditions. Chromatographic peak identification was performed with authentic reference compounds of the enantiomers and on-line UV spectra comparison. This method was applied to the determination of the enantiomeric ratio of phenprocoumon in plasma and urine extracts from patients under racemic drug therapy. The limit of detection (50 and 80 ng/ml) and precision (less than 5%) of the method are adequate for pharmacokinetic and enantioselective disposition studies, respectively, of phenprocoumon. No racemization was detected during the extraction procedures.

Induction of stress proteins by sodium chloride treatment in Bacillus subtilis

In Bacillus subtilis, heat shock proteins can be classified into two main groups: specific heat shock proteins (about 5) and general stress proteins (at least 14). Salt stress was very effective in the induction of general stress proteins (5 to 50-fold stimulation), but the synthesis of heat-specific stress proteins was not stimulated. Furthermore there were some proteins whose synthesis was accelerated only by salt stress.

Biliary excretion of phenprocoumon and metabolites

To evaluate phenprocoumon elimination its possible biliary excretion was evaluated in addition to the known pathway of renal elimination. Bile samples were obtained during diagnostic endoscopy in patients receiving chronic phenprocoumon therapy and were analyzed for phenprocoumon and its metabolites by HPLC and GC-MS. The following substances were detected, mainly in conjugated form: unchanged phenprocoumon and the metabolites 7-hydroxy-, 4'-hydroxy-, and 6-hydroxy-phenprocoumon. The data provide direct evidence of the biliary elimination of unchanged phenprocoumon and its metabolites in humans.