Stereospecific positioning of the cis-acting sequence with respect to the canonical promoter is required for activation of the ompC gene by a positive regulator, OmpR, in Escherichia coli

Expression of the ompC gene coding for a major outer-membrane protein of Escherichia coli is regulated by a transcriptional activation mechanism that requires the ompR gene product, OmpR. It was demonstrated that multiple OmpR molecules bind to a cis-acting sequence located upstream from the canonical -35 and -10 regions of the ompC promoter. Using an ompC-lacZ fusion gene, the distance between the cis-acting upstream sequence (OmpR-binding site) and the -35 and -10 regions (RNA polymerase-binding site) has been changed. We demonstrated that the ompC transcription was activated in an OmpR-dependent manner even when the cis-acting upstream sequence was separated from the -35 and -10 regions by several turns of the DNA helix, providing that the distance between them was a near-integral multiple of one turn of the DNA helix. Evidence is presented that stereospecific positioning of the cis-acting upstream sequence with respect to the canonical promoter is required for activation of the ompC gene by the positive regulator, OmpR.

[Acute promyelocytic leukemia with central nervous system leukemia--a report of two cases]

Two cases of promyelocytic leukemia (APL) with central nervous system leukemia (CNS-L) are reported. The first case displayed some symptoms similar to meningitis at onset, and the second case, during induction therapy suddenly developed left hemiplegia and was found to have CNS-L. There have been only a few case reports of APL associated with CNS-L and each has said that APL was rarely accompanied by CNS-L. Yet, of the reports registered with the Joint Committee for Hematologic neoplasm in Japan, the incidence of APL with CNS-L is not much lower than any of the other types of acute non-lymphocytic leukemia that can accompany a CNS-L. There fore, we feel that CNS-L should not be overlooked as an important prognostic consideration in APL cases.

Pepsinogen gene transcription induced in heterologous epithelial-mesenchymal recombinations of chicken endoderms and glandular stomach mesenchyme

Proventricular (glandular stomach) mesenchyme of chicken embryos can induce endoderms of some parts of embryonic digestive tract to produce embryonic chicken pepsinogen (ECPg), a marker protein for the differentiation of embryonic proventricular epithelium. In the present study, we investigated the production of ECPg mRNA in the course of epithelial-mesenchymal interactions between endoderms of digestive tract and proventricular mesenchyme. ECPg mRNA was detected by Northern hybridization with ECPg cDNA as a probe. In normal development of the proventriculus, ECPg mRNA was first detected at day 7 of incubation, and it ceased to be produced by day 21. Embryonic esophagus, gizzard and small intestine did not contain ECPg mRNA. When 6-day esophagus, gizzard or proventricular endoderm was associated and cultured with 6-day proventricular mesenchyme, the recombinates formed proventricular-gland-like complex glands and produced ECPg mRNA in almost equal quantity. However, 6-day small intestinal or 3.5-day allantoic endoderm did not produce pepsinogen mRNA under the same conditions, though the recombinates formed complex glands. These results indicate that the proventricular mesenchyme can induce de novo transcription of ECPg gene in esophagus, proventricular and gizzard endoderms, and that ECPg gene in small intestinal and allantoic endoderms fails to react to the inducing signal.

Morphometrical and biochemical analysis on autofluorescent granules in various tissues and cells of the rats under several nutritional conditions

The effects of age and nutritional conditions on accumulation of autofluorescent granules in various organs and tissues of male Sprague-Dawley rats were compared morphometrically. The relative intensity of the specific fluorescence of these autofluorescent granules was similar in all tissues and cells examined. In almost all cases, there were more autofluorescent granules in the 12-month experiment than in the 4-month one. Multiple necrotic foci of myofibrils with an accumulation of autofluorescent granules were seen in striated muscles in the rats on vitamin E-deficient diets for 12 months. In splenocytes, renal proximal convoluted tubules and hepatic cells, autofluorescent granules quantitatively increased significantly with an increase of the corn oil contents in the diets. The increase was rather marked in the splenocytes and renal epithelia of vitamin E-deficient rats. In the Purkinje cells and bronchial epithelial cells, no significant differences were noted according to the difference in the vitamin E and corn oil contents in diets. The accumulation of autofluorescent granules was not merely considered to be an age-related change, but to be influenced by a relationship to the cell metabolism and functional activity in various organs.

Isolation and structural analysis of embryonic chicken pepsinogen gene: avian homologue of prochymosin gene

Embryonic chicken pepsinogen gene was isolated from a chicken genomic library. This gene occupied approximately 3.5 kb of the genomic DNA and was separated into nine exons by eight introns. The positions of exon-intron junctions coincided with those in the human pepsinogen A gene and the bovine prochymosin gene. Southern blot analysis of chicken genomic DNA revealed that the structure of the isolated gene reflects the original structure in the chicken chromosome. At the same time, the presence of another copy of embryonic pepsinogen gene was suggested. 5'-flanking region of the isolated ECPg gene was analyzed.

Effects of penetration enhancers on percutaneous absorption of nifedipine. Comparison between Deet and Azone

The influence of N, N-diethyl-m-toluamide (Deet) and 1-dodecylazacycloheptan-2-one (Azone), on skin permeability was examined for nifedipine (NP), taking into account their effects on the thermodynamic activity of the drug. The percutaneous absorption efficiency of NP was determined by measuring the drug concentration in rat plasma. Comparisons were made among NP suspensions in the enhancers to ensure equal thermodynamic activity. Azone increased NP penetration over that of propylene glycol (PG), while Deet produced a similar response to that of PG. The addition of a small amount of Deet to PG or diethyl sebacate (DES) provided for a rather large increase in NP penetration compared with that from PG or DES alone. The results of this study strongly suggest that Deet and Azone have different modes of action. Azone exerted a genuine effect on the skin and produced marked improvement in the penetration of NP. The effect of Deet was interesting as it was effective only in combination with other vehicles. Deet exhibits excellent solubilizing properties and penetrates the skin easily. Accordingly, it may be concluded that Deet functions simply as a cosolvent to produce saturated or supersaturated solutions of the active ingredient by its rapid disappearance from the vehicle, and thereby maximizes the thermodynamic activity of the drug.

Molecular cloning and the nucleotide sequence of cDNA for embryonic chicken pepsinogen: phylogenetic relationship with prochymosin

Embryonic chicken pepsinogen is an aspartyl proteinase that is specifically secreted during the embryonic period in the chicken proventriculus (glandular stomach). To learn the phylogeny of this pepsinogen, we isolated a cDNA clone by screening a lambda gt11 library of embryonic proventricular cDNAs with an antiserum to the embryonic chicken pepsinogen. We obtained a 200-base pair cDNA clone which encoded 18 amino acids that had high sequence homology with the carboxyl termini of other pepsinogens. Northern blot analysis revealed that this cDNA clone hybridized to a mRNA of 1,600 bases in the embryonic proventriculus but not to the mRNA in the adult proventriculus. The almost complete nucleotide sequence of embryonic chicken pepsinogen-cDNA was determined by sequencing longer cDNAs obtained by screening the same library with the 200-base pair cDNA and primer extension with a synthetic primer. The cDNA consisted of 1,281 nucleotides and encoded 383 amino acids for prepepsinogen. The predicted amino acid sequence was compared with the sequences of other aspartyl proteinases: pepsinogen A of human, monkey, pig, and chicken, progastricsin of monkey and rat, and bovine prochymosin. The phylogenetic tree constructed for them indicates the possibility that embryonic chicken pepsinogen diverged from prochymosin, after prochymosin and pepsinogen A had diverged from each other.

Interaction of OmpR, a positive regulator, with the osmoregulated ompC and ompF genes of Escherichia coli. Studies with wild-type and mutant OmpR proteins

The OmpR protein is a positive regulator involved in osmoregulatory expression of the ompC and ompF genes that specify the major outer membrane proteins OmpC and OmpF, respectively. We purified the OmpR protein not only from wild-type cells but also from two ompR mutants (ompR2 and ompR3) exhibiting quite different phenotypes as to osmoregulation of the ompC and ompF genes. The OmpR2 protein has an amino acid conversion in the C-terminal portion of the OmpR polypeptide, whereas the OmpR3 protein has one in the N-terminal portion. Comparative studies on these purified OmpR proteins were carried out in terms of their interaction with the ompC and ompF promoters. The nucleotide sequences involved in OmpR-binding were determined in individual promoter regions by deoxyribonuclease I footprinting. The OmpR3 protein as well as the wild-type OmpR protein appeared to bind, to similar extents, to both the ompC and ompF promoters. In contrast, the OmpR2 protein bound preferentially to the ompF promoter and failed to protect the ompC promoter against DNAse I digestion. These results support the view that the C-terminal portion of the OmpR protein is responsible for the binding of the OmpR protein to the ompC and ompF promoter DNAs. Based on these results, the structure and function of the OmpR protein are discussed in relation to the mechanism of osmoregulation.

Presence of pepsinogens immunoreactive to anti-embryonic chicken pepsinogen antiserum in fish stomachs: possible ancestor molecules of chymosin of higher vertebrates

1. Stomachs of adult teleosts and elasmobranchs reacted to an anti-embryonic chicken pepsinogen antiserum (anti-ECPg) as well as to an anti-adult chicken pepsinogen antiserum (anti-ACPg). 2. Zymograms and immunoblots of stomach extracts revealed that anti-ECPg- and anti-ACPg-reactive substances possess peptic activity. 3. The possible relationship between anti-ECPg-reactive pepsinogens in fish and prochymosins in higher vertebrates is discussed.

Molecular assembly of the lipoprotein trimer on the peptidoglycan layer of Escherichia coli

The molecular assembly of the major outer membrane lipoprotein on the peptidoglycan layer was studied using two hybrid genes coding for different OmpF-lipoprotein hybrid proteins. One gene codes for a "lipoprotein" in which the diacylglyceryl cysteine residue is replaced with the Ala-Glu residue of the NH2 terminus of the OmpF protein (hybrid protein I). The other gene codes for the lipid-free "lipoprotein" from which the COOH-terminal lysine residue was further deleted (hybrid protein II). Hybrid protein I existed as a trimer. A significant portion of it was found to be composed of only the free form, which was noncovalently associated with the peptidoglycan layer. The purified hybrid protein I trimer was dissociated into the subunit in the presence of guanidine-HCl and reassociated on dialysis. Both the native and reassociated trimers were bound to the lipoprotein-free peptidoglycan layer. No enhancement of the binding was observed when the reassociation reaction was carried out simultaneously. Hybrid protein II, on the other hand, did not exhibit association with peptidoglycan in both the cellular fractionation and in vitro binding experiments, although it existed as a trimer. It is concluded that 1) the protein domain of the lipoprotein exists as a trimer which is noncovalently as well as covalently associated with the peptidoglycan layer and 2) although the deletion of the COOH terminal lysine residue did not interfere with the trimerization, it interfered with the noncovalent interaction with the peptidoglycan layer.

Random cloning of bent DNA segments from Escherichia coli chromosome and primary characterization of their structures

A simple method for the selective detection of DNA segments containing a sequence-directed static bend was developed. Two-dimensional polyacrylamide gel electrophoresis performed at two different temperatures (60 degrees C and 10 degrees C) can effectively separate a bent DNA from a mixture of normal DNA. Using this method, a bank of plasmids carrying bent DNA inserts from the E. coli total chromosome was constructed. The primary characterization of a set of bent DNA segments randomly cloned from E. coli was presented.

Use of a series of ompF-ompC chimeric proteins for locating antigenic determinants recognized by monoclonal antibodies against the ompC and ompF proteins of the Escherichia coli outer membrane

A method is presented for the efficient location of antigenic determinants using a series of chimeric proteins. By means of in vivo homologous recombination between the ompC and ompF genes coding for OmpC and OmpF, homologous proteins of the Escherichia coli outer membrane, a series of ompF-ompC chimeric genes was constructed (Nogami, T., Mizuno, T., & Mizushima, S. (1985) J. Bacteriol. 164, 797-801, and this work). The OmpF-OmpC chimeric proteins expressed by these genes were successfully used to locate antigenic determinants recognized by monoclonal antibodies, which specifically react with either the OmpC or OmpF protein. Interaction between monoclonal antibodies and the chimeric proteins was examined by means of either enzyme-linked immunosorbent assay or immunoblot analysis. The antigenic determinants recognized by three anti-OmpC antibodies and one anti-OmpF antibody were thus located. Finally, the polypeptides covering these regions were chemically synthesized for two of them and then tested as to their reactivity with the antibodies. The peptides reacted with the corresponding antibodies when the former were chemically coupled with bovine serum albumin. Most of the monoclonal antibodies isolated in this work were highly specific to the unfolded monomer of the protein against which the antibody was raised. But they did not react with the trimer, the native form. These results are discussed in relation to the structures and functions of the OmpC and OmpF proteins. The use of a series of monoclonal antibodies for studying the mechanism of protein translocation across the cytoplasmic membrane is also discussed.

Total organic carbon as an index for specification of water for injection

Determination of organic compounds present as contaminants in purified water is of great importance. Total organic carbon (TOC) may be a useful parameter for evaluating the purity of water. This paper describes and compares the analytical results for solutions of 12 model compounds obtained by 3 methods: total organic carbon (TOC) analysis, determination of potassium permanganate consumption, and UV spectroscopy. TOC analysis gave values corresponding to the expected amounts of organic carbon for all the model compounds, whereas the other 2 methods gave highly variable results.

Change of mosaic pattern by androgens during prostatic bud formation in XTfm/X+ heterozygous female mice

The testicular feminization (Tfm) gene, which is characterized by a deficiency in androgen receptors, is located on the X-chromosome. Using steroid autoradiography, the mosaicism of the Tfm gene has been demonstrated in the androgen target tissues of XTfm/X+ heterozygous female mouse fetuses and the effects of androgens on the mosaic pattern analysed. In the mesenchyme of urogenital sinuses of wild-type female fetuses (X+/X+), more than 95% of the cells were androgen-receptor positive (labelled with [3H]testosterone) while in that of heterozygous fetuses (XTfm/X+), only half of the cells were receptor positive (Tfm gene inactive), and receptor-positive cells and -negative cells formed small irregular patches. When the heterozygous sinuses were cultured in vitro in the presence of androgens, the sinuses underwent male sexual development and formed epithelial buds (prostate gland rudiments) projecting into the surrounding mesenchyme. Autoradiographic analysis revealed that the mosaicism of the mesenchyme disappeared around the developing epithelial buds: almost all the mesenchymal cells in close vicinity to the buds were receptor positive while in the outer layers receptor-positive and -negative cells coexisted. The proportion of receptor-positive cells was greatly increased in the mesenchyme beneath the non-budding area of the sinus epithelium. This androgen-induced increase was observed before the onset of bud formation. The results obtained in the thymidine incorporation experiments suggest that the increase of receptor-positive cells beneath the sinus epithelium might be explained by the migratory behaviour of the androgen-incorporating cells rather than by their selective proliferation.

Visualization of X-chromosome inactivation mosaicism of Tfm gene in XTfm/X+ heterozygous female mice

The testicular feminization (Tfm) locus, which produces a deficiency in androgen receptors, is located on the X-chromosome. Steroid autoradiographic techniques were used to demonstrate the mosaicism of the X-chromosome inactivation in two androgen target tissues of XTfm/X+ heterozygous female mice. In the mesenchyme of urogenital sinuses of wild-type female fetuses (X+/X+), more than 95% of the cells were androgen-receptor positive (labelled with [3H]testosterone) while in that of heterozygous fetuses (XTfm/X+), about half of the cells were receptor positive (Tfm gene inactive). Statistical analysis of coherent clone size was applied to the heterozygous mesenchyme of the urogenital sinus and the coherent clone size of receptor-positive cells was estimated to be two or three cells per clone. This small clone size suggests that considerable cell mixing occurred in the tissue during embryonic development. Androgen binding in the mammary gland rudiments was restricted to the mesenchymal cells only in close vicinity to the epithelial mammary bud. In the wild-type rudiments most of the mesenchymal cells beneath the epithelium were receptor positive, while in heterozygous rudiments, receptor-positive and -negative cells intermingled. This observation suggests that in the wild-type mammary gland rudiments the epithelial bud may induce the formation of androgen receptors in adjacent mesenchymal cells rather than attract pre-existing receptor-rich mesenchymal cells.

Function of micF as an antisense RNA in osmoregulatory expression of the ompF gene in Escherichia coli

To analyze the function of micF as an antisera RNA in the osmoregulatory expression of the ompF gene in Escherichia coli, we performed two experiments. In the first experiment, two strains were constructed in which the transcription initiation site of the ompF gene and the transcription termination site of the micF gene were separated by 186 and 4,100 base pairs, respectively, on the chromosome. These two strains showed almost the same profile of ompF expression as the wild-type strain in which the two genes are separated by 10(6) base pairs. When a high-copy-number plasmid carrying the micF gene was introduced into these strains, ompF expression was completely repressed, whereas no repression was observed with a low-copy-number plasmid carrying the micF gene. These results indicate that the distance between the two genes on the chromosome is not critical for the function of micF. In the second experiment, expression of the ompF gene was examined by pulse-labeling in both the micF+ and the micF deletion strains. Upon a shift from a low- to a high-osmolarity medium, suppression of OmpF protein synthesis occurred more quickly and more extensively in the micF+ strain than in the micF deletion strain. The steady-state synthesis of the OmpF protein was also completely suppressed in the micF+ strain in the high-osmolarity medium, whereas the suppression was incomplete in the micF deletion strain. From these results we conclude that (i) the micF gene contributes to the fast and complete response of the OmpF synthesis to the medium osmolarity, and that (ii) the distance between the micF and ompF genes on the chromosomes is not critical for the function of the micF gene. The results suggest, rather, that the ratio of the copy numbers of the two genes is critical for the function of the micF gene.

Gland formation of human colon cancer cells combined with foetal rat mesenchyme in organ culture: an ultrastructural study

The morphogenetic potential of human colon cancer cells was examined by combining cells with foetal rat mesenchyme in organ culture. Out of four cell lines examined, LS174T cells formed glandular structures composed of a simple columnar or cuboidal epithelium with a lumen in the centre of the cell mass. Ultrastructurally, these gland-forming LS174T cells exhibited polarity, with nuclei located basally, microvilli projecting into the lumen, tight junctions at the cell—cell junction facing the lumen, desmosomes at the subluminal region, and basal laminae at the epithelial-mesenchymal interface. Other cell lines did not form such glandular structures, while some cells could form microvilli, tight junctions or basal laminae, which were arranged randomly. It is concluded that it is not the existence but the ordered arrangement of these structures that is essential for gland formation by epithelial cells. The mechanism of gland formation is discussed with special reference to the arrangement of different structures.

Construction of a series of ompC-ompF chimeric genes by in vivo homologous recombination in Escherichia coli and characterization of their translational products

OmpC and OmpF are major outer membrane proteins and although they are homologous proteins, they function differently in several respects. As an approach to elucidate the submolecular structures that determine their differences, we have constructed a series of ompC-ompF chimeric genes by in vivo homologous recombination between these two genes, which are adjacent on a plasmid. The recombination sites in the chimeric genes were localized by means of restriction endonuclease analysis and nucleotide sequence determination. Most of the chimeric gene products were accumulated in the outer membrane. One of the chimeric gene products, with a fusion site in a central region between the OmpC and OmpF proteins, was normally expressed but not accumulated in the outer membrane. The trimeric structures of some of the chimeric gene products appeared to be extremely unstable in a SDS solution. From these results, domains contributing to the formation of specific structures in which the OmpC and OmpF proteins differ were identified. Bacterial cells possessing the chimeric gene products were also investigated as to their sensitivity to phages that require either OmpC or OmpF as a receptor component. With the aid of the chimeric gene products, the immunogenic determinants for three anti-OmpC monoclonal antibodies were found to be localized at different portions of the OmpC polypeptide: the N-terminal, central and C-terminal portions, respectively.

Preservation of natural killer and interleukin-2 activated killer cell activity in ataxia-telangiectasia with T cell deficiency

Peripheral blood mononuclear cells (PBMs) from 6 patients with ataxia-telangiectasia (AT) were studied by 5 kinds of cell-mediated cytotoxicity systems. Decrease in cell mediated lympholysis (CML) activity to allogeneic lymphocytes was observed in all 6 AT patients who had low numbers of OKT-3+ cells. These patients also showed decreased proliferative responses to phytohemagglutinin stimulation and allogeneic lymphocytes. In contrast, antibody-dependent cell-mediated cytotoxicity (ADCC) activity and natural killer (NK) activity were comparable with those in normal controls. In addition, PBMs from these AT patients activated by in vitro stimulation with allogeneic PBMs or interleukin-2 were able to acquire lytic activity against NK-insensitive target cells. The phenotypes of these effectors determined by complement-mediated lysis were OKT-3- and Leu-11+, suggesting that they were derived from NK cell lineage. Thus, AT patients with severe T cell defects were found to maintain a normal range of NK, ADCC, MLC-activated and lymphokine-activated killer activity.

Intramural giant gallstone: report of a rare case

We report a case of intramural giant gallstone. Cholangiography revealed narrowing of the neck of the gallbladder due to a hemispherical prominence. At cholecystectomy, a giant gallstone 2.1 cm in diameter which was located in the submucosa of a hemispherical prominence at the neck of the gallbladder, was found. Although the usual sizes of intramural gallstones mentioned in previous reports have ranged from 2 to 5 mm in diameter, the stone found in our case is, as far as we know, the largest intramural gallstone yet reported.

Roles of the Pribnow box in positive regulation of the ompC and ompF genes in Escherichia coli

The roles of the first base of the Pribnow box in positive regulation of the ompC and ompF genes were studied. G- and A-to-T substitutions of the first base of the ompC and ompF Pribnow boxes, respectively, resulted in a high-level functioning of the promoters in the ompR background. The level was further enhanced significantly in the ompR+ background. The effects of other substitutions were also studied. Based on these observations, the roles of the Pribnow box in the positive regulation are discussed.

Isolation and characterization of deletion mutants of ompR and envZ, regulatory genes for expression of the outer membrane proteins OmpC and OmpF in Escherichia coli

Expression of the ompC and ompF genes coding for the major outer membrane proteins, OmpC and OmpF, respectively, is known to be controlled by at least two regulatory genes, ompR and envZ, which together comprise a single ompB operon. We constructed chromosomal mutants with either ompR-envZ deletion or envZ deletion. Characterization of these deletion strains showed that the OmpR protein is necessary for transcription of the ompC and ompF genes, and the EnvZ protein is essential for normal regulation of the ompC and ompF expression, which is affected by the medium osmolarity. We also constructed several plasmids carrying different portions of the ompB operon. Characterization of these plasmids allowed us to identify the OmpR protein with an apparent molecular weight of 29 kilodaltons (kDa) and the EnvZ protein with an apparent molecular weight of 50 kDa. The initiation codon for EnvZ translation appeared to overlap with the termination codon for OmpR translation. It was also found that a truncated EnvZ polypeptide (44 kDa) which lacks the N-terminal 55 amino acid residues can complement the envZ deletion mutant. Based on these results, the structure and function of the ompB operon are discussed in relation to the regulation of ompC and ompF expression.

Phenol: a complex chemoeffector in bacterial chemotaxis

Earlier observations that phenol is a repellent for Salmonella typhimurium but an attractant for Escherichia coli were confirmed. This behavioral difference was found to correlate with a difference in the effect phenol had on receptor methylation levels; it caused net demethylation in S. typhimurium but net methylation in E. coli. On the basis of mutant behavior and measurement of phenol-stimulated methylation, the attractant response of E. coli was shown to be mediated principally by the Tar receptor. In S. typhimurium, two receptors were found to be sensitive to phenol, namely, an unidentified receptor, which mediated the repellent response and showed phenol-stimulated demethylation; and the Tar receptor, which (as with E. coli) mediated the attractant response and showed phenol-stimulated methylation. In wild-type S. typhimurium, the former receptor dominated the Tar receptor, with respect to both behavior and methylation changes. However, when the amount of Tar receptor was artificially increased by the use of Tar-encoding plasmids, S. typhimurium cells exhibited an attractant response to phenol. No protein analogous to the phenol-specific repellent receptor was evident in E. coli, explaining the different behavioral responses of the two species toward phenol.

Static bend of DNA helix at the activator recognition site of the ompF promoter in Escherichia coli

Expression of the ompF gene coding for a major outer membrane protein of Escherichia coli is regulated by osmolarity of the medium. The ompF expression is controlled by a transcriptional activation mechanism which requires the ompR gene product acting on a region located upstream from the canonical -35 and -10 regions of the ompF gene. Evidence is presented that the upstream region of the ompF promoter contains a static bend of DNA having two sets of oligo (dA X dT) tracts with periodical spacing. It was demonstrated that the bending region overlaps with the recognition site for the activator protein, OmpR.

Interaction between two regulatory proteins in osmoregulatory expression of ompF and ompC genes in Escherichia coli: a novel ompR mutation suppresses pleiotropic defects caused by an envZ mutation

The ompR and envZ genes, which together constitute the ompB operon, are involved in osmoregulatory expression of the OmpF and OmpC proteins, major outer membrane proteins of Escherichia coli. The envZ11 mutation results in the OmpF- OmpC-constitutive phenotype. A mutant which suppressed defects caused by the envZ11 mutation was isolated. The suppressor mutation also suppressed the LamB- PhoA- phenotype caused by the envZ11 mutation. The mutation occurred in the ompR gene and hence was termed ompR77. The ompR77 mutation alone produced no obvious phenotype. Functioning of the ompR77 allele remained envZ gene dependent. Although the ompR77 mutation suppressed the envZ11 mutation, it did not suppress a mutation that occurred in another position within the envZ gene (envZ160). These results indicate that OmpR and EnvZ, two regulatory proteins, functionally interact with each other.

Purification and characterization of the OmpR protein, a positive regulator involved in osmoregulatory expression of the ompF and ompC genes in Escherichia coli

The OmpR protein is a positive regulator involved in osmoregulatory expression of the ompF and ompC genes, which respectively code for major outer membrane proteins OmpF and OmpC of Escherichia coli. The OmpR protein has been purified to homogeneity from an overproducing strain harboring an ompR gene-carrying plasmid. Throughout the purification the OmpR protein behaved as a single entity. The molecular weight determined on sodium dodecyl sulfate-polyacrylamide gel, the total amino acid composition, and the NH2-terminal amino acid sequence of the purified protein were essentially the same as those deduced from the nucleotide sequence of the ompR gene. Molecular weight determination and cross-linking study on the native protein revealed that the purified protein exists as a monomer. The purified OmpR protein was specifically bound to the promoter regions of the ompC and ompF genes. Experiments with a series of upstream deletions of the ompC and ompF promoters revealed that the region upstream from the -35 region was indispensable for OmpR binding to both the ompC and the ompF promoters. Although it has been proposed that depending on the medium osmolarity the OmpR protein may exist in two alternative structures, which respectively regulate functioning of the ompC and the ompF promoters, the purified OmpR protein appeared to be homogeneous and interacted with both promoters to the same extent.

Characterization by deletion and localized mutagenesis in vitro of the promoter region of the Escherichia coli ompC gene and importance of the upstream DNA domain in positive regulation by the OmpR protein

The ompC gene codes for a major outer membrane protein whose expression is regulated by the ompR and envZ genes. Two sets of promoter deletion mutants, with upstream and downstream deletions, were constructed on a plasmid in vitro, and their promoter activity was studied by connecting them with the lacZ gene. The DNA sequence for the ompC promoter, including the -35 and -10 regions and the mRNA start site, was defined at the region about 100 base pairs upstream from the ATG initiation codon for the pro-OmpC protein. An additional 61-base-pair sequence extending upstream from the -35 region was required for the ompC promoter to function fully. After targeting the upstream region of the ompC promoter fused to the lacZ gene on a plasmid, in vitro-localized mutagenesis was performed to isolate cis-dominant mutations that affect ompC transcription. Four mutant groups, each of which had common phenotypes for expression and regulation of the gene, were identified. The individual groups also had common base substitutions. In two of the groups, the common base substitutions were localized in the upstream region of the ompC promoter, whereas in the other two they were localized in the -35 region. From these results, the upstream region of the ompC promoter was considered to be the domain responsible for activation by the ompR gene product.

Complementation analysis of the wild-type and mutant ompR genes exhibiting different phenotypes of osmoregulation of the ompF and ompC genes of Escherichia coli

Expression of the ompF and ompC genes, which encode the major outer membrane proteins, OmpF and OmpC, respectively, is affected in a reciprocal manner by the osmolarity of the growth medium. This osmoregulation is mediated by the OmpR protein, a positive regulator of both genes, which is encoded by the ompR gene. Structural and functional properties of this regulatory protein were studied through complementation analysis of the wild-type and five mutant ompR genes that exhibited differences in osmoregulation of the expression of the OmpF and OmpC proteins. Complementation was carried out with combinations of a host strain and a plasmid, each of which carried either the wild-type or a mutant ompR gene. In some combinations, negative complementation was observed. For example, ompR1, a deletion mutation with an OmpF- OmpC- phenotype, was dominant to OmpF+ or OmpC+ phenotypes conferred by other ompR genes. Positive complementation of two mutant ompR genes was also observed in other combinations, when the two mutations were distantly located from each other on the OmpR protein. These results, together with other observations, support the view that the OmpR protein has a two-domain structure, each domain exhibiting a different role in the expression of the OmpF and OmpC proteins, and that this protein takes a multimeric structure as a functional unit.

In vitro analysis of lymphocyte functions in common variable immunodeficiency: heterogeneity in B-cell defects

Ten patients with common variable immunodeficiency were classified into three groups according to the number of circulating B-cells, i.e. B-cells being absent (three patients), very low (three patients) or within the normal range (four patients). The four patients in the last group showed significant proliferative responses to the T-independent B-cell mitogen, formalin-fixed Staphylococcus aureus, Cowan I. Further study of these patients by co-cultures with allogeneic T or B-cells in various combinations with pokeweed mitogen showed that two patients had an intrinsic B-cell defect without T-cell defect. The third patient had a T-cell dysfunction (i.e. his T-cells could only help the B-cells of some individuals) resulting in a defect in Ig production. The T-cells of the fourth patient showed poor helper function towards all controls. All six patients with absent or very low numbers of B-cells in group I and II had normal T-cell helper function. This study demonstrates that the immunological defect in common variable immunodeficiency is most often a B-cell defect at different stages of their differentiation with sometimes an additional T-cell dysfunction.

Analysis of prostatic bud induction by brief androgen treatment in the fetal rat urogenital sinus

The androgen dependency of prostatic bud formation in fetal rat urogenital sinuses was studied using brief treatments with androgen, and the incorporation of androgens by the sinus mesenchyme was followed by steroid autoradiography. Urogenital sinuses from 16.5-day fetuses of both sexes were grown in organ culture and treated with androgens for periods ranging from 4 to 72 h and then transferred to control medium. A minimum treatment of 24 h was required to induce prostatic buds in male sinuses and of 36 h in all female sinuses. This difference in response disappeared after more prolonged treatment. In both sexes the number of prostatic buds increased with the time of exposure to androgens. Prostatic bud formation continued for 24-36 h after transfer to control medium. Steroid autoradiographic analysis showed that the labelled androgen was concentrated in the mesenchymal nuclei. The rate of incorporation rose steeply during the first 12 h and then more slowly. After transfer to control medium the amount of labelled androgen decreased rapidly to half within 12 h and then decreased more slowly. In the competition experiments a 200-fold excess of unlabelled testosterone or dihydrotestosterone in the labelling medium greatly reduced the nuclear labelling with [3H]testosterone.

Long-term follow-up of ten patients with Lesch-Nyhan syndrome

Ten cases of Lesch-Nyhan syndrome have been followed for 3-19 years (mean, 11 years and four months). Criteria of Lesch-Nyhan syndrome were restricted to the following: complete absence of hypoxanthine-guanine phosphoribosyltransferase (HPRT) in hemolysate and fibroblast, spasticity, choreoathetosis, mental retardation, self-mutilation, and occurrence in males. Two patients have died of pneumonia and two died suddenly. However, autopsies produced no positive findings. Hyperuricemia has been controlled by benzbromarone in nine patients. One patient did not take any medical treatment and died suddenly when he was 19 years old, but showed no gouty signs. Patients with Lesch-Nyhan syndrome indicated no change or aggravation of choreoathetosis or spasticity. Self-mutilation was difficult to control by any treatment with continuing effect. After the age of ten, self-mutilation declined in seven cases, and in one patient disappeared completely. Mental delay was remarkable and suspected developmental age (DA) was 7 months - four years and 10 months (chronological age, 7 years and five months - 19 years and 6 months). Mean DQ score was 15.6. Physical development was severely delayed, and weight age was 28.9-46.4%, mean 37.4% of chronological age. Future investigations will evolve clarification of CNS signs and its treatment, and etiological research of sudden death.

Trimeric structure and localization of the major lipoprotein in the cell surface of Escherichia coli

A hybrid gene consisting of the ompF promoter, the coding regions for the signal peptide, and the Ala-Glu residue of the OmpF NH2 terminus and the coding region for the major outer membrane lipoprotein devoid of the NH2-terminal cysteine residue was constructed. Escherichia coli carrying the cloned gene produced the predicted hybrid protein that is the same as the major lipoprotein except that the diacyl glycerylcysteine residue at the NH2 terminus is replaced by the Ala-Glu residue. The hybrid protein was localized in the periplasmic space as a trimer with a noncovalent interaction in addition to the previously known covalent interaction with the peptidoglycan. These results strongly indicate that the major lipoprotein exists as a trimer in the periplasmic space with covalent and noncovalent interactions with the peptidoglycan layer through the protein domain on one side and with the hydrophobic interaction with the outer membrane through the lipid domain on the other side. The trimeric structure of the lipoprotein was directly demonstrated by the chemical cross-linking of the native lipoprotein with both cleavable and uncleavable reagents. The cross-linking study also revealed interaction between the lipoprotein and the OmpA protein, a major outer membrane protein.

[Exercise tolerance in mitral stenosis and chronic obstructive pulmonary disease: evaluation by anaerobic threshold and radionuclide ventriculography]

Serial radionuclide ventriculography was performed using a newly developed "real-time" system, and left ventricular ejection fraction (LVEF), right ventricular ejection fraction (RVEF), stroke volume (SV), and cardiac output (CO) were measured during graded supine exercise in five patients with mitral stenosis (MS), in five patients with chronic obstructive pulmonary disease (COPD) and in five healthy subjects. Simultaneous pulmonary gas exchange analysis permitted determining the anaerobic threshold, which is the point during incremental exercise when lactate begins to accumulate in the blood. LVEF at the anaerobic threshold was not significantly changed in any patient groups and in healthy subjects, but RVEF at the anaerobic threshold was lower in COPD and MS patients as compared with healthy subjects. In MS, SV during exercise was reduced at the anaerobic threshold, but not in COPD or in healthy subjects. In conclusion, reduced working capacity is related to decreased RVEF in both COPD and MS, but the inhibited increase in CO during exercise is also important for the working capacity in MS.

Direct coupling of micro high-performance liquid chromatography with fast atom bombardment mass spectrometry. II. Application to gradient elution of bile acids

A new system without a moving belt has been developed for direct coupling of micro high-performance liquid chromatography with fast atom (xenon or argon) bombardment mass spectrometry. The structure of the interface was basically the same as used previously, but the mass spectrometer was modified by adding both a liquid nitrogen trap between the ion source housing and the diffusion pump, and a position adjuster for the interface. Stable ionization of the solute in a glycerol matrix is achieved at flow-rates below 2 microliter/min. The system was applied to the analysis of bile acids by gradient elution chromatography. Steady baselines were observed in the mass chromatograms.

Morphogenesis of human colon cancer cells with fetal rat mesenchymes in organ culture

The morphogenesis and cytodifferentiation of human colon cancer cells (LS174T and HT29) were examined by combining cancer cells with fetal rat digestive-tract mesenchyme in organ culture. LS174T cells migrated into the mesenchyme to form glandular structures composed of single columnar cells with their nuclei oriented basally, while HT29 cells formed cell masses with little lumen formation. Immunohistochemical studies with antibodies against carcinoembryonic antigen and secretory components showed that the composition of cell surface glycoproteins was not necessarily reversed to the normal type, even when neoplastic cells exhibited normal glandular structures.

Acquisition of maltose chemotaxis in Salmonella typhimurium by the introduction of the Escherichia coli chemosensory transducer gene

Escherichia coli and Salmonella typhimurium are closely related species. However, E. coli cells show maltose chemotaxis but S. typhimurium cells do not. When an E. coli chemotransducer gene (tarE), the product of which is required for both aspartate and maltose chemotaxis, was introduced by using a plasmid vector into S. typhimurium cells with a defect in the corresponding gene (tarS), the transformant cells acquired the ability for both aspartate and maltose chemotaxis. In contrast, when the tars gene was introduced into tarE-deficient E. coli cells, the transformant cells acquired aspartate chemotaxis but not maltose chemotaxis. These results indicate that the absense of maltose chemotaxis in S. typhimurium is a consequence of the properties of the tars gene product.