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S Taira

Publications and source records attributed to S Taira.

At least 19 recordsLinked to original sources
PubMed1992

A new alpha-helical coiled coil protein encoded by the Salmonella typhimurium virulence plasmid.

A new protein of Salmonella typhimurium was identified and characterized. The gene (tlpA) encoding this protein (TlpA) was isolated from the large virulence-associated plasmid of S. typhimurium and sequenced in order to predict the primary structure of TlpA. tlpA encodes a 371-amino acid soluble protein with a calculated M(r) of 41600 and pI of 4.63. Secondary structure predictions and sequence statistics of TlpA indicated a predominant alpha-helical configuration and presence of heptapeptide repeat motifs characteristic of coiled coil proteins. Purified TlpA was shown to have biochemical properties similar to those of coiled coil proteins, including adoption of an alpha-helical configuration and a tendency to form homodimers. Furthermore, TlpA possessed heat resistance, evidence for a chain register and altered mobility in urea/sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels which are characteristics of tropomyosins. TlpA shows 32% overall sequence similarity with rat cardiac myosin and 36% similarity with horse platelet beta-tropomyosin over 226 residues, whereas selected regions possessed significant sequence identities with myosins, tropomyosins, and alpha-helical surface proteins of Streptococcus pyogenes. Our results indicate that TlpA represents a new member of prokaryotic coiled coil proteins.

Amino Acid Sequence↗
PubMed1992

The virulence plasmid does not contribute to growth of Salmonella in cultured murine macrophages.

The virulence plasmid, characteristic of many serovars of Salmonella sp., and specifically its spv genes, promote intracellular growth of the bacteria in the liver and spleen and are essential for the virulence of these Salmonella serovars in the mouse. In an attempt to establish an in vitro model for studying its function, we evaluated its effect on the intracellular growth of the bacteria in macrophages in culture. We used a number of different macrophage-like cell lines (J774-A.1, IC-21 and PU5-1.8), as well as peritoneal or splenic macrophages from genetically Salmonella-sensitive (Itys, BALB/c) or resistant (Ityr, C3H/HeN) mice, and at different states of activation, stimulated in vivo or in vitro with lipopolysaccharide and/or recombinant gamma interferon. These were found to differ in their ability to suppress or sustain intracellular growth of several Salmonella serovars, but in all cases the growth was independent of the spv genes.

Animals↗
PubMed1992

Plasmid-mediated serum resistance in Salmonella enterica.

The ability of Salmonella enterica to survive an incubation of 2 h in fresh, pooled guinea-pig serum was determined comparing strain sets of serovariants Dublin and Typhimurium, harbouring or lacking the virulence plasmid. All strains showed marked serum resistance, which was slightly decreased among cured strains of Typhimurium. However, when introduced into a rough Escherichia coli strain, all Typhimurium plasmids substantially increased the resistance of the host strain to guinea-pig serum, whereas the Dublin plasmid did not. The traT gene, previously shown to affect serum resistance, was identified on all Typhimurium plasmids, but not on the Dublin plasmid. Mutational inactivation of the traT gene on the Typhimurium plasmids eliminated the serum resistance mediated by the plasmids.

Animals↗
PubMed1992

[Detection of Epstein-Barr virus DNA in salivary gland tumors].

To evaluate the relations between salivary gland tumors and Epstein-Barr virus (EBV), the levels of EBV-related antibodies were examined, and detection of EBV nuclear antigen (EBNA) and EBVDNA in tumor tissue was attempted by the anti-complement immunofluorescence technique and polymerase chain reaction, respectively. The mean VCA-IgG antibody level was increased to 925 (80-2560) in Warthin's tumor, 496 (40-2560) in mucoepidermoid tumor, and 206 (40-640) in pleomorphic adenoma. The positive rate of EA-IgG was high in Warthin's and mucoepidermoid tumors. VCA-IgA antibody was positive in 2 of the 7 cases of Warthin's tumor. EA-IgA antibody was negative in all cases. EBVDNA was detected in 7 of the 7 cases of Warthin's tumor, 3 of the 5 cases of mucoepidermoid tumor, and 2 of the 26 cases of pleomorphic adenoma. A relationship between Warthin's tumor and EBV was suggested by the 100% detection rate of the viral DNA.

Adenolymphoma↗
PubMed1991

Amino-terminal sequence analysis of four plasmid-encoded virulence-associated proteins of Salmonella typhimurium.

We have expressed four virulence-associated proteins encoded by the Salmonella typhimurium plasmid pEX102 in Escherichia coli. The genes coding for the proteins MkaA, MkaB, MkaC and MkaD subcloned in the vectors pUC19 or Bluescript KS+ directed substantial production of these proteins in E. coli. The same host harbouring pEX102 did not produce these proteins in detectable amounts. The proteins were exclusively found in the particulate fraction. The amino-terminal sequence analysis showed that the N-termini of these proteins corresponded to the ones predicted from the open reading frames found previously in the DNA sequence of the virulence determinant and that no N-terminal signal sequence processing of the proteins occurred.

Amino Acid Sequence↗
PubMed1991

The mkaC virulence gene of the Salmonella serovar typhimurium 96 kb plasmid encodes a transcriptional activator.

The intracellular growth and virulence of Salmonella serovar Typhimurium for mice is dependent on a plasmid-borne gene cluster termed mka. We studied the regulatory interactions of the genes mkaA, mkaB, mkaC and mkaD using lacZ gene fusions. Complementation experiments with cloned DNA fragments encoding each of the four MKa proteins indicated that mkaC enhances the expression of beta-galactosidase from the mkaA-, mkaB- and mkaC-lacZ gene fusions in trans. An mkaD-lacZ fusion or mkaA-lacZ fusion that did not contain DNA proximal to mkaB was not inducible with MkaC, indicating that at least mkaB and mkaA are induced together as an operon. MkaC is thus the first virulence protein whose function has been resolved.

Escherichia coli↗
PubMed1990

Nucleotide sequence of mkaD, a virulence-associated gene of Salmonella typhimurium containing variable and constant regions.

We have identified the nucleotide (nt) sequence of mkaD, a virulence-associated gene of the Salmonella typhimurium virulence plasmid, pEX102. The gene shows 98% homology on nt sequence level to mkfA, a corresponding gene of the S. typhimurium virulence plasmid pIP1350. The few nt changes, however, caused more extensive changes on the amino-acid level. The differences between mkaD and mkfA were clustered in distinct variable regions rather than being randomly scattered along the sequence. A third salmonellar virulence plasmid, pLT2, contained an mkaD gene identical to that of pEX102. Our observation suggests that the conserved virulence determinant on the plasmids of Salmonellae may contain different alleles of the same gene.

Amino Acid Sequence↗
PubMed1990

Production and secretion of pertussis toxin subunits in Bacillus subtilis.

Pertussis toxin (PT) is a major component of today's acellular whooping cough vaccines. The use of acellular vaccines is predicted to increase sharply in the near future. There is therefore a need to produce PT in a way that makes its purification as easy as possible. Our approach was to express all five PT subunits individually in Bacillus subtilis. We have used vectors containing the promoter and signal sequences of the alpha-amylase gene of Bacillus amyloliquefaciens followed by an insert encoding the appropriate PT-subunit. All PT-subunits were secreted and found in the culture supernatant. The level of expression varied considerably: S1 and S5 were produced in large quantities whereas much smaller amounts of S2, S3 and S4 were found. The subunits were also present in the membrane fraction of the respective strains.

Amino Acid Sequence↗
PubMed1990

Eye movement analysis system using computerized image recognition.

A new technique for an eye movement analysis system utilizing infrared video recording and a computerized image recognition method is presented. The system consists of an infrared lighting apparatus, a very small infrared video charge-coupled device camera, a video tape recorder, an analogue-digital converter, and microcomputers. This system makes it possible to simultaneously analyze the slow-phase velocity quantitatively not only of the horizontal and vertical but also of the rotatory components of the energy-induced nystagmus. The maximum slow-phase velocity of the rotatory component of energy-induced nystagmus was found to be 4.1 degrees per second on an average in this study.

Adult↗
PubMed1990

Efficacy of the high molecular weight fraction of plasma for the maintenance of pregnancy associated with thrombotic thrombocytopenic purpura.

We have investigated the methods for the maintenance of a pregnancy in a patient with thrombotic thrombocytopenic purpura (TTP), said condition, since 1984, having been controlled by a plasma infusion every 3 to 4 weeks. In a preliminary trial it was confirmed that an infusion of the high molecular weight fraction (HMW-F) of plasma, separated by an Evaflux 2A fractionator, improved the patient's thrombocytopenia as the plasma infusion, and maintained its beneficial effect for about 2 weeks during early pregnancy. Though an occurrence of a toxemia-like syndrome responded to repeated plasma infusion, the dose of plasma required to improve the thrombocytopenia gradually increased and reached 5,040 ml by the 20th week of pregnancy. Thus, instead of periodic infusions of whole plasma, periodic infusions of the HMW-F of plasma were used. Under this regimen the platelet count remained above 10.0 x 10(4)/microliters during late pregnancy, and the total dose (2,600 ml) of HMW-F of plasma that was administered until delivery at full term was less than the dosage of whole plasma that was used during early pregnancy. In this manner we were able to obtain a healthy baby by controlling the patient's TTP during pregnancy. This method of preventing thrombocytopenia appears to be safer with respect to volume loading during pregnancy in the TTP patient.

Adult↗
PubMed1990

Expression of pertussis toxin subunit S4 as an intracytoplasmic protein in Bacillus subtilis.

The expression and secretion of pertussis toxin subunits S1 to S5 in Bacillus subtilis by the aid of a bacillary signal sequence has been reported. While secretion of subunit S1 was high, that of others was low. Ways have now been explored to improve the yield, using S4 as an example. The addition of a protease inhibitor was found to increase the amount of S4 in the culture supernatant, but the final amount was still much below that of S1. However, intracellular expression of S4 gave a high yield (500 mg l-1) and the aggregated protein could easily be isolated in a few simple steps.

Amino Acid Sequence↗
PubMed1989

Molecular organization of genes constituting the virulence determinant on the Salmonella typhimurium 96 kilobase pair plasmid.

The ability of intracellular growth is plasmid-dependent in Salmonella typhimurium. Only a small portion of this 96 kilobase pair plasmid appears essential for intracellular growth. The genetic organization of this region (the essential virulence determinant) was resolved. Fragments of the virulence determinant were cloned from the 96-kb plasmid pEX102 and transformed into minicell-producing E. coli. Plasmid-directed protein synthesis was investigated in metabolically labeled minicells. This analysis indicated the presence of at least four genes, mkaA, mkaB, mkaC and mkaD, within the virulence determinant encoding proteins of 70, 31, 30 and 29 kDa, respectively. The genes were positioned on the restriction map of the 96-kb virulence plasmid and the map locations confirmed by nucleotide sequence analysis of two new virulence genes (mkaB and mkaC).

Amino Acid Sequence↗
PubMed1989

Production of pneumolysin, a pneumococcal toxin, in Bacillus subtilis.

We have expressed the pneumolysin gene of Streptococcus pneumoniae in Bacillus subtilis, both from its own promoter and as a fusion protein. The level of expression of pneumolysin from its own promoter was low. The protein produced was hemolytically active. A higher level of expression (about 10 micrograms/ml of culture) was achieved when either one of two C-terminal fragments (corresponding to amino acids 265-471 and 55-471, respectively) or the entire coding part of the pneumolysin gene were fused to the promoter and signal sequence-coding region of the alpha-amylase gene of Bacillus amyloliquefaciens. The C-terminal fusion peptides reacted with anti-pneumolysin serum, but were not hemolytically active. In both cases most of the peptide remained cell-associated. When the entire pneumolysin gene was fused to the signal sequence, a hemolytically active form of pneumolysin could be detected, and most of the product was found in a processed form in the culture supernatant. The full-length pneumolysin secreted from B. subtilis was partially purified and used as antigen in an enzyme immunoassay with rabbit anti-pneumolysin serum.

Bacillus subtilis↗
PubMed1989

Identification and genetic analysis of mkaA--a gene of the Salmonella typhimurium virulence plasmid necessary for intracellular growth.

Salmonella typhimurium, like many other Salmonella serovars, harbours a large plasmid required for mouse virulence and growth of bacteria in host cells. The nature of one virulence-abolishing Tn5 insertion (zzx-2556::Tn5) in the plasmid was characterized. A 3.7 kb insert harbouring this region was cloned in pBR325. Plasmid-directed protein synthesis in minicells indicated that the transposon had eliminated the expression of a 70 kDa protein encoded by the virulence plasmid. Nucleotide sequence analysis of the corresponding wild type DNA region showed a 1773 bp open reading frame (mkaA), encoding a protein of 591 amino acid residues and a predicted molecular mass of 60.6 kDa; zzx-2556::Tn5 was situated within mkaA.

Base Sequence↗
PubMed1988

Possible role of neuraminidase in activated T cells in the recognition of allogeneic Ia.

In a primary MLR, predominant stimulators in spleen cells are adherent cells and not B cells, although B cells are one of the cell types expressing a large amount of Ia molecules. Our previous experiments showed that T cells treated with neuraminidase (Nase) responded to an allogeneic Ia on B cells. In our experiments, the relationship between the responsiveness to the allogeneic Ia molecules on B cells and Nase activity of T cells was examined. The results showed that T cells increased in Nase activity with the acquisition of the reactivity to Ia on B cells. T cells from normal mice increased in Nase activity after the incubation for 3 days or more in MLR, and these T cells responded to allogeneic Ia on B cells. However, T cells from mice genetically deficient in Nase responded poorly to the Ia on allogeneic B cells even after the incubation in MLR for 3 days. T cells incubated for 3 days in MLR decreased in electrophoretic mobility, indicating the decrease of net negative charge of the cells, and increased in their binding of peanut agglutinin which has been reported to bind to galactosyl residues exposed on T cell surface by removing sialic acids. These results suggest that Nase in T cells was activated by the cultivation in MLR for 3 days, and sialic acids of some molecules on T cell surface were removed by the enzyme and, in turn, T cells acquired the responsiveness to allogeneic B cells in a secondary MLR. Thus, Nase was suggested to play a regulatory role in the recognition of Ia molecules in T cells.

Animals↗
PubMed1987

Interleukin secretion by B cell lines and splenic B cells stimulated with calcium ionophore and phorbol ester.

A B cell lymphoma A20.2J and splenic B cells produced an active material to support the proliferation of an interleukin 2 (IL-2)-dependent T cell line, CTLL-2, by stimulation with both calcium ionophore A23187 and phorbol myristate acetate (PMA). Although the production of the active material was induced by stimulation with A23187 alone in A20.2J cells, both A23187 and PMA were essential for the stimulation of splenic B cells. Neither A20.2J cells nor splenic B cells produced the active material by stimulation with PMA alone. The production was inversely proportional to the concentration of fetal calf serum in culture medium. The active material produced by B cells was indicated to be IL-2 and not B cell-stimulating factor 1 (BSF-1) for the following reasons: 1) the proliferation of CTLL-2 cells in the presence of active material was inhibited by the inclusion of anti-IL-2 receptor or anti-IL-2 in culture medium but not by anti-BSF-1; 2) the material showed no co-mitogenic activity to purified splenic B cells with anti-immunoglobulins and did not support the proliferation of FDC-P2 which are known to grow in the presence of BSF-1; and 3) IL-2 mRNA could be detected in A20.2J and splenic B cells stimulated with A23187 and PMA in Northern blot analysis. Some B cell hybridomas were also shown to produce IL-2 by similar stimulation to A20.2J. Splenic B cells as well as A20.2J cells were able to produce IL-2 by stimulation with anti-immunoglobulins. These results suggest that under certain conditions IL-2 can be produced by splenic B cells, at least some subsets of B cells, and B cell lines.

Animals↗