Upper gastrointestinal bleeding in patients in chronic hemodialysis.
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Adult↗
Biomedical subjects
N Kido
Publications and source records attributed to N Kido.
Autoimmune myocarditis induced in mice by cardiac C-protein. Cloning of complementary DNA encoding murine cardiac C-protein and partial characterization of the antigenic peptides.
Autoimmune myocarditis is considered to play a major role in the pathogenesis of dilated cardiomyopathy. A new autoimmune myocarditis model was attained by repeated immunization using murine cardiac C-protein with the immunological adjuvant, Klebsiella pneumoniae O3 lipopolysaccharide. For further analysis of a pathological epitope, the cDNA encoding C-protein was isolated; a fusion protein encoded by part of this cDNA induced myocarditis in SMA mice as well as in three other strains: DBA/1J (H-2q), O20/A (H-2pz1), and SJL (H-2s). The nucleotide sequence and its deduced amino acid analysis revealed that this protein had immunoglobulin-like and fibronectin-like repeats. This study provides a new animal model of autoimmune myocarditis which may shed light on the pathogenesis of dilated cardiomyopathy.
Adult↗
Polymorphism of crystals of Salmonella minnesota Re and Ra lipopolysaccharides.
Salmonella minnesota Re and Ra lipopolysaccharides (LPSs) formed three-dimensional crystals when they were precipitated by the addition of 2 volumes of 95% ethanol containing 375 mM MgCl2 and incubated in 70% ethanol containing 250 mM MgCl2 at 4 C. Besides typical shapes of crystals, hexagonal plates and solid columns, which were already reported (J. Bacteriol. 172: 1516-1528 (1990)), the LPSs thus treated formed crystals possessing various shapes such as square or rectangular plate, lozenge plate, discoid, and truncated hexangular pyramid forms. Electron diffraction patterns from all these crystals except square or rectangular plate crystals obtained by electron irradiation from the direction perpendicular to the basal plane were essentially the same as those from hexagonal plate crystals, indicating that they consist of hexagonal lattices with the lattice constant of 4.62 A. From these results as well as the results of electron microscopic observations of these crystals, it was concluded that all these crystals except square or rectangular plate crystals are composed of hexagonal plate sheets as the basic structural units. Square or rectangular crystals were assumed to correspond to the (1011) planes of solid hexagonal column crystals.
Crystallography↗
Isolation of rfb gene clusters directing the synthesis of O polysaccharides consisting of mannose homopolymers and serological analysis of lipopolysaccharides.
Four serotypes of two genera, Escherichia coli O8 and O9 and Klebsiella O3 and O5, produce the O polysaccharides consisting of mannose homopolymers. Previously, we reported the isolation and expression of E. coli O9 rfb in E. coli K-12 strains (Kido et al, J. Bacteriol., 171: 3629-3633, 1989). In this study, R' plasmids carrying his-rfb region of the other three strains were isolated and expressed in E. coli K-12 strain. Serological study of lipopolysaccharides (LPS) synthesized in E. coli K-12 strain was carried out. His-linked rfb genes from E. coli O9 and Klebsiella O3 directed the synthesis of O polysaccharides with the same antigenicity as those of the parental strains in E. coli K-12 strain. On the other hand, rfb genes from E. coli O8 and Klebsiella O5 directed the synthesis of O polysaccharides which were antigenically not identical but partially common to those of the parental strains. A rough strain derived from E. coli O8 synthesized LPS which showed the identical antigenicity as the wild strain when the his-rfb region of E. coli O8 was introduced. The results suggest that some genes located distantly from his are additionally required to complete the synthesis of O polysaccharides of E. coli O8 and Klebsiella O5.
Carbohydrate Conformation↗
Experimental murine model for autoimmune myocarditis using Klebsiella pneumoniae O3 lipopolysaccharide as a potent immunological adjuvant.
Experimental autoimmune myocarditis could be produced in mice by repeated injection of syngeneic heart extract together with Klebsiella pneumoniae O3 lipopolysaccharide (KO3 LPS) as a powerful adjuvant. Histological changes in the cardiac lesions were characterized by infiltration with mononuclear cells in the myocardium, degeneration and loss of myocardial fibers, and replacement of granulation tissues. No such cardiac lesions were produced in mice receiving injections of heart extract alone or KO3 LPS alone. Development of the autoantibody and the delayed type-hypersensitivity (DTH) against syngeneic heart extract was found in mice immunized repeatedly with the mixture of heart extract and KO3 LPS. Moreover, definite cardiac lesions were produced in normal recipient mice by transfer of sensitized spleen cells from hyperimmunized mice. Therefore, it was suggested that those cardiac lesions were caused by the autoimmune mechanism. Our methodology provided a new experimental murine model for autoimmune myocarditis.
Adjuvants, Immunologic↗
Gamete development in Plasmodium berghei regulated by ionic exchange mechanisms.
Ionic regulation in the induction of exflagellation of Plasmodium berghei was investigated by culturing the parasites in various isotonic media. Of the salts tested, NaHCO3 exhibited the highest activity in inducing exflagellation, whereas KHCO3 showed no activity. In the absence of HCO3-, media containing monovalent cation (Na+, K+, Cs+, Rd+, choline+, lysine+, arginine+) and Cl- also induced exflagellation, but their activities were lower than that of NaHCO3. Anions of Br- or NO3- could be substituted with Cl-, whereas other anions such as I-, NO2-, SO4(2-), SCN-, H2PO4-, or HPO4(2-) failed to induce exflagellation, as did tetramethylammonium-Cl, CaCl2, MgSO4, MgCl2 and sucrose as well. These results suggest that the induction of exflagellation requires the presence of Na+ and HCO3- or monovalent, membrane-permeable cation and Cl- in the medium. Measurements of the efflux of H[14C]O3- or Cl- indicated that these anions were released from the cells into the NaCl or the NaHCO3 medium, respectively, probably by exchange in HCO3-/Cl-. Determination of intracellular ionic concentrations by electron microscopic X-ray microanalysis of cryopreserved specimens revealed that in the NaHCO3 medium, external Na+ (and probably HCO3-) enters the gametocytes by exchange with internal Cl- (and probably H+), whereas in Cl(-)-containing media, external unspecified cation and Cl- influx by exchange, probably with H+ and HCO3-. It is therefore suggested that two separate ion exchangers, i.e., Na(+)-dependent HCO3-(in)/Cl-(out) and nonspecific monovalent-cation-dependent Cl-(in)/HCO3-(out) exchangers, are involved in the induction of gametogenesis in P. berghei.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
[Visual agnosia evolving to optic aphasia--a case study].
The underlying mechanism of visual agnosia and optic aphasia has not been fully elucidated, although a number of hypotheses have been proposed. Besides, the difference between these two conditions has been a matter of debate. We report here the result of neuropsychological evaluation in a case of associative visual agnosia evolving to optic aphasia. A 64-year-old right-handed patient was found to be disoriented and confused after undergoing the operation of gastrectomy. CT scan revealed a large infarction in the territory of left posterior cerebral artery. Since 3 weeks after onset, neuropsychological investigations were carried out during 5 months. He was alert and co-operative. Right homonymous hemianopia with macular sparing was noted, but his visual acuity was normal. There was neither a global deterioration of intellectual capacities nor aphasia. Most striking finding was his difficulty in identifying common objects and colours along with a profound alexia. Prosopagnosia was absent. Visual naming both for objects and line drawings was severely impaired. He was unable to describe or demonstrate the use of the objects which could not be named. Pointing to objects named by the examiner was also severely impaired. Although tactile naming was also impaired, both of auditory naming for environmental sounds and naming objects in response to verbal descriptions were preserved. While he was not able to copy the objects skillfully, matching of identical objects and matching objects to line drawings were normal. Clumsiness of coping was thought to be due to his constructional apraxia and visuomotor ataxia. Therefore, his deficit in visual domain was considered to be associative visual agnosia.(ABSTRACT TRUNCATED AT 250 WORDS)
Agnosia↗
Cloning and expression of the rfe-rff gene cluster of Escherichia coli.
We have cloned a 13 kb Escherichia coli DNA fragment which complemented the rfe mutation to recover the biosynthesis of E. coli O9 polysaccharide. Using Tn5 insertion inactivation, the rfe gene was localized at the 1.5 kb HindIII-EcoRI region flanking the rho gene. We constructed an rfe-deficient E. coli K-12 mutant by site-directed inactivation using a DNA fragment of the cloned 1.5 kb rfe gene. This also confirmed the presence of the rfe gene in the 1.5 kb region. By simultaneous introduction of both the rfe plasmid and the plasmid of our previously cloned E. coli O9 rfb into this rfe mutant, we succeeded in achieving in vivo reconstitution of O9 polysaccharide biosynthesis. From sequence analysis of the rfe gene, a putative promoter followed by an open reading frame (ORF) was identified downstream of the rho gene. This ORF coincided with the position of the rfe gene determined by Tn5 analysis and site-directed mutagenesis. Furthermore, we identified the rff genes in the 10.5 kb DNA flanking the rfe gene. We recognized at least two functional domains on this cloned rff region. Region I complemented a newly found K-12 rff mutant, A238, to synthesize the enterobacterial common antigen (ECA). Deletion of region II resulted in the synthesis of ECAs with shorter sugar chains. When the 10.5 kb rff genes of the plasmid were inactivated by either deletion or Tn5 insertion, the plasmid lost its ability to give rise to transformants of the rfe mutants.
Amino Acid Sequence↗
Increased resistance to multiple drugs by introduction of the Enterobacter cloacae romA gene into OmpF porin-deficient mutants of Escherichia coli K-12.
Introduction of the romA gene cloned from Enterobacter cloacae into Escherichia coli K-12 resulted in almost complete inhibition of OmpF expression and a concomitant increase in resistance to quinolones, beta-lactams, chloramphenicol, and tetracyclines. In addition, the romA gene reduced the susceptibility to these multiple drugs even in the OmpF porin-deficient mutants of E. coli K-12. Results indicate the presence of romA-sensitive penetration pathway(s) for these multiple drugs other than the OmpF porin in E. coli.
Anti-Bacterial Agents↗
Possible mechanisms underlying the slow lactose fermentation phenotype in Shigella spp.
A Southern hybridization analysis revealed that the region homologous to Escherichia coli lacZ was present on the chromosomal DNAs of beta-galactosidase-positive Shigella strains, such as Shigella dysenteriae serovar 1 and Shigella sonnei strains, whereas this region was absent from chromosomal DNAs of beta-galactosidase-negative strains of Shigella flexneri and Shigella boydii. We found that the lacY-A region was deficient in S. dysenteriae serovar 1 and believe that this is the reason for the slow fermentation of lactose by this strain. S. sonnei strains possessed the region which hybridized with E. coli lacY-A despite their slow hydrolysis of lactose. The whole lactose-fermenting region was cloned from S. sonnei and compared with the cloned lac operon of E. coli K-12. Both clones directed the synthesis of beta-galactosidase in an E. coli K-12 strain lacking indigenous beta-galactosidase activity (strain JM109-1), and we observed no difference in the expression of beta-galactosidase activity in S. sonnei and E. coli. However, E. coli JM109-1 harboring the lactose-fermenting genes of S. sonnei exhibited the slow lactose fermentation phenotype like the parental strain. S. sonnei strains had no detectable lactose permease activities. E. coli JM109-1 harboring the lactose-fermenting genes of S. sonnei had a detectable permease activity, possibly because of the multicopy nature of the cloned genes, but this permease activity was much lower than that of strain JM109-1 harboring the lac operon of E. coli K-12. From these results we concluded that slow lactose fermentation by S. sonnei is due to weak lactose permease activity.
Blotting, Southern↗
Biosynthesis of Klebsiella K2 capsular polysaccharide in Escherichia coli HB101 requires the functions of rmpA and the chromosomal cps gene cluster of the virulent strain Klebsiella pneumoniae Chedid (O1:K2).
The genes determining the biosynthesis of type 2 (K2) capsular polysaccharide [3----beta Glc1,4----beta Man(1,3----beta GlcUA) 1,4----alpha Glc1----] of Klebsiella pneumoniae Chedid (O1:K2), which is highly virulent for mice, were cloned and introduced into Escherichia coli HB101 and into four noncapsulated mutants derived from K. pneumoniae reference strains of K1, K7, K9, and K28. The recombinant plasmid pCPS7B06 carried 23 kb of a chromosomal DNA fragment of strain Chedid and encoded a part of the Klebsiella cps gene cluster. However, pCPS7B06 encoded enough genetic information for the production of Klebsiella K2 capsular polysaccharide on the cell surfaces of four noncapsulated mutants of K. pneumoniae. On the other hand, both pCPS7B06 and pROJ3 carrying the rmpA gene locus derived from a resident large plasmid of Chedid were required for the biosynthesis of Klebsiella K2 capsular polysaccharide on the cell surface of E. coli HB101. The insertion inactivation analysis using Tn5 revealed that the cps gene cluster occupied more than 15 kb of the chromosome of Chedid. We conclude that rmpA, which has been known to enhance the biosynthesis of colanic acid in E. coli, is also involved in the biosynthesis of Klebsiella capsular polysaccharide in E. coli HB101.
Animals↗
Expression of the cloned Escherichia coli O9 rfb gene in various mutant strains of Salmonella typhimurium.
To investigate the effect of chromosomal mutation on the synthesis of rfe-dependent Escherichia coli O9 lipopolysaccharide (LPS), the cloned E. coli O9 rfb gene was introduced into Salmonella typhimurium strains defective in various genes involved in the synthesis of LPS. When E. coli O9 rfb was introduced into S. typhimurium strains possessing defects in rfb or rfc, they synthesized E. coli O9 LPS on their cell surfaces. The rfe-defective mutant of S. typhimurium synthesized only very small amounts of E. coli O9 LPS after the introduction of E. coli O9 rfb. These results confirmed the widely accepted idea that the biosynthesis of E. coli O9-specific polysaccharide does not require rfc but requires rfe. By using an rfbT mutant of the E. coli O9 rfb gene, the mechanism of transfer of the synthesized E. coli O9-specific polysaccharide from antigen carrier lipid to the R-core of S. typhimurium was investigated. The rfbT mutant of the E. coli O9 rfb gene failed to direct the synthesis of E. coli O9 LPS in the rfc mutant strain of S. typhimurium, in which rfaL and rfbT functions are intact, but directed the synthesis of the precursor. Because the intact E. coli O9 rfb gene directed the synthesis of E. coli O9 LPS in the same strain, it was suggested that the rfaL product of S. typhimurium and rfbT product of E. coli O9 cooperate to synthesize E. coli O9 LPS in S. typhimurium.
Agglutination↗
Cloning and expression of rfe gene.
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Antigens, Bacterial↗
Cloning and analysis of rfb gene synthesizing the mannan 0 side chain of Escherichia coli 09 lipopolysaccharide.
The rfb gene encoding the proteins responsible for the synthesis of the repeating units (O side-chain) of Escherichia coli 09 lipopolysaccharide was cloned into a conjugative plasmid RP4::miniMu and was expressed in E. coli K-12.
Antigens, Bacterial↗
Interaction of Mg2+ and Ca2+ in in vitro hexagonal assembly of R-form lipopolysaccharides.
The R-form lipopolysaccharide (LPS) from Klebsiella pneumoniae strain LEN-111 (03-:Kl-), from which cationic material had been removed by electrodialysis, formed an orderly hexagonal lattice structure when suspended in 50 mM Tris buffer at pH 8.5 containing MgCl2. The center-to-center distance (lattice constant) of the hexagonal lattice structure depended upon the concentration of MgCl2 and reached the shortest value (15 nm) at 10 mM. In contrast, CaCl2 could not produce the orderly hexagonal lattice structure but produced an irregular network structure with a center to center distance of 19 to 20 nm. When the LPS was suspended in Tris buffer containing 10 mM MgCl2 mixed with 1 or 10 mM CaCl2, formation of the orderly hexagonal lattice structure of the magnesium salt type was inhibited and the LPS showed the structure of the calcium salt type. When 1 or 10 mM CaCl2 was mixed with 10 mM MgCl2, the binding of Mg to the LPS was significantly inhibited compared with when 10 mM MgCl2 was added alone. On the contrary, when 10 mM CaCl2 was mixed with 10 mM MgCl2, the binding of Ca to the LPS was enhanced compared with when 10 mM CaCl2 was added alone. It was therefore concluded that the inhibition of formation of the hexagonal lattice structure of the magnesium salt type by addition of CaCl2 is due to the inhibition of the binding of Mg to the LPS. Such a competitive interaction of Mg2+ and Ca2+ was also observed with the electrodialyzed LPS of Escherichia coli K-12.
Calcium↗
Relationship between Mg2(+)-induced hexagonal assembly of R-form lipopolysaccharides and chemical structure of their R-cores.
The relationship between formation of the Mg2(+)-induced hexagonal lattice structure by R-form lipopolysaccharides (LPS) and chemical structure of their R-cores was investigated using different kinds of R-form LPS from a series of mutants of Salmonella minnesota or S. typhimurium. The optimal experimental condition for formation of the hexagonal lattice structure was to suspend LPS preparations, from which cationic material was removed by electrodialysis, in 50 mM tris (hydroxymethyl) aminomethane buffer at pH 8.5 containing 10 mM MgCl2. Under this experimental condition, Rb1 LPS formed the hexagonal lattice structure with the lattice constant of 14.0 +/- 0.2 nm. Ra LPS, which possesses the full length of R-core, also formed the hexagonal lattice structure but its lattice constant was larger (18.1 +/- 0.2 nm) than that of Rb1 LPS (the lattice structure by Ra LPS was looser than that by Rb1 LPS). All the other R-form LPS preparations tested, RcP+, PcP-, Rd1P-, and Re LPS, whose R-cores are shorter than that of Rb1 LPS, did not form the hexagonal lattice structure, but formed membranous structures showing various shapes which consisted of multiple bilayer structures. Failure to form the hexagonal lattice structure was the common feature of these kinds of R-form LPS irrespective of temperature at which the LPS suspensions in 10 mM MgCl2-50 mM Tris buffer were incubated. From the results of the present study it was concluded that capability of R-form LPS to form the hexagonal lattice structure has a close correlation with the chemical structure of their R-cores.
Carbohydrate Sequence↗
Inhibitory effect of Ca2+ on formation of Mg2(+)-mediated two-dimensional hexagonal lattice structure by an R-form lipopolysaccharide from Klebsiella pneumoniae.
When the R-form lipopolysaccharide (LPS) from Klebsiella pneumoniae strain LEN-111 (O3-:K1-), from which cationic material had been removed by electrodialysis, was suspended in 50 mM Tris buffer at pH 8.5 containing 0.1 mM or higher concentrations of MgCl2, it formed an ordered two-dimensional hexagonal lattice structure and its center-to-center distance (lattice constant) depended upon the concentration of MgCl2 and reached the shortest value (14 nm) at 10 mM. In contrast, in the presence of 0.1 to 10 mM CaCl2 in place of MgCl2, the electrodialyzed LPS did not form such an ordered hexagonal lattice structure but formed an irregular network structure with a center-to-center distance of 19 to 20 nm. We investigated interaction of Mg2+ and Ca2+ in formation of the hexagonal lattice structure by the electrodialyzed LPS suspended in 50 mM Tris buffer at pH 8.5. When 0.1 mM or higher concentrations of CaCl2 were mixed with 1 mM MgCl2 or when 1 mM or higher concentrations of CaCl2 was mixed with 10 mM MgCl2, the electrodialyzed LPS did not form the hexagonal lattice structure of the magnesium salt type but formed the irregular network structure of the calcium salt type. In the coexistence of equimolar or higher concentrations of CaCl2 together with 1 or 10 mM MgCl2, the binding of Mg to the electrodialyzed LPS was significantly inhibited and, conversely, the binding of Ca was enhanced as compared with when MgCl2 or CaCl2 was present alone. However, the coexistence of 10 times less molar concentrations of CaCl2 did not significantly inhibit the binding of Mg to the electrodialyzed LPS. Therefore, the inhibition of formation of the Mg2(+)-mediated hexagonal lattice structure of the electrodialyzed LPS by equimolar or higher concentrations of CaCl2 accompanied the inhibition of binding of Mg but that by 10 times less molar concentrations of CaCl2 did not accompany it.
Calcium↗
Rapid small-scale preparation method of cell surface polysaccharides.
A rapid small-scale method of extraction of lipopolysaccharide (LPS) and capsular polysaccharides was developed for the purpose of identification of chemotypes of LPS and serotypes of capsular antigens. Cell surface polysaccharides were prepared within less than 2 hr from 1.5 ml of broth or suspension of colonies cultured overnight. The preparations were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis for LPS, and by double diffusion gel precipitation (Ouchterlony) test and blotting to nitrocellulose membrane for capsular polysaccharide. The analyses with the preparations obtained by the method could provide adequate results capable of identifying chemotypes of LPS and serotypes of capsular antigens.
Antigens, Bacterial↗