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Y Terawaki

Publications and source records attributed to Y Terawaki.

At least 19 recordsLinked to original sources
PubMed1999

The complete nucleotide sequence of phi CTX, a cytotoxin-converting phage of Pseudomonas aeruginosa: implications for phage evolution and horizontal gene transfer via bacteriophages.

phi CTX is a cytotoxin-converting phage isolated from Pseudomonas aeruginosa. In this study, we determined the complete nucleotide sequence of the phi CTX phage genome. The precise genome size was 35,538 bp with 21 base 5'-extruding cohesive ends. Forty-seven open reading frames (ORFs) were identified on the phi CTX genome, including two previously identified genes, ctx and int. Among them, 15 gene products were identified in the phage particle by protein microsequencing. The most striking feature of the phi CTX genome was an extensive homology with the coliphage P2 and P2-related phages; more than half of the ORFs (25 ORFs) had marked homology to P2 genes with 28.9-65.8% identity. The gene arrangement on the genome was also highly conserved for the two phages, although the G + C content and codon usage of most phi CTX genes were similar to those of the host P. aeruginosa chromosome. In addition, phi CTX was found to share several common features with P2, including the morphology, non-inducibility, use of lipopolysaccharide core oligosaccharide as receptor and Ca(2+)-dependent receptor binding. These findings indicate that phi CTX is a P2-like phage well adapted to P. aeruginosa, and provide clear evidence of the intergeneric spread and evolution of bacteriophages. Furthermore, comparative analysis of genome structures of phi CTX, P2 and other P2 relatives revealed the presence of several hot-spots where foreign DNAs, including the cytotoxin gene, were inserted. They appear to be deeply concerned in the acquisition of various genes that are horizontally transferred by bacteriophage infection.

Amino Acid Sequence↗
PubMed1999

Molecular cloning, sequencing, purification, and characterization of Pseudomonas aeruginosa ribosome recycling factor.

Ribosome recycling factor (RRF) is required for release of 70S ribosomes from mRNA on reaching the termination codon for the next cycle of protein synthesis. The RRF-encoding gene (frr) of Pseudomonas aeruginosa PAO1 was functionally cloned by using a temperature-sensitive frr mutant of Escherichia coli and sequenced. The P. aeruginosa frr was mapped at 30 to 32 min of the P. aeruginosa chromosome. The deduced amino acid sequence of RRF showed a 64% identity to that of E. coli RRF. In an assay including E. coli polysome and elongation factor G, purified recombinant RRF of P. aeruginosa released monosomes from polysomes. This is the first case in which an RRF homologue was found to be active in heterogeneous ribosome recycling machinery. The genes for ribosomal protein S2 (rpsB), elongation factor Ts (tsf), and UMP kinase (pyrH) are located upstream of frr. The arrangement of the genes, rpsB-tsf-pyrH-frr, resembles those reported for E. coli and Bacillus subtilis. Even in the cyanobacterium genome, the arrangement pyrH-frr is conserved. Although RRF homologues are found in eukaryotic cells, phylogenetic analysis suggests that they were originally present within the members of the phylogenetic tree of prokaryotic RRF. This finding suggests that the ribosome recycling step catalyzed by RRF is specific for prokaryotic cells and that eukaryotic RRF is required for protein synthesis in organelles, which are believed to be phylogenetically originated from prokaryotes.

Amino Acid Sequence↗
PubMed1998

Purification and characterization of procytotoxin of Pseudomonas aeruginosa. Dimer to monomer conversion of protoxin by proteolytic activation.

Cytotoxin of Pseudomonas aeruginosa is a cytolytic toxin that forms a pore on the target membrane by oligomerizing into a pentamer. This toxin is produced as an inactive precursor (proCTX) and is converted to an active form by proteolytic cleavage at the C terminus. We purified proCTX to apparent homogeneity and characterized it in a comparison with the active toxin. ProCTX bound to the erythrocyte membrane but did not form an oligomer on the membrane, hence the lack of hemolytic activity in proCTX. Circular dichroic experiments showed that active and proCTX have similar beta-sheet dominant structures. Intrinsic fluorescence analysis indicated that a molecule-buried tryptophan residue(s) of proCTX was exposed to the surface of the molecule as a result of conversion to the active form. In analytical gel filtration, chemical cross-linking, and analytical ultracentrifugation experiments, dimer to monomer conversion occurred with proteolytic activation.

Animals↗
PubMed1998

Functional domains of Rts1 and P1 RepA proteins for initiation of replication.

Rts1 RepA and P1 RepA are trans-acting proteins essential for initiation of replication of Rts1 and P1 plasmids, respectively. We recently found that P1 RepA bound in vitro to the Rts1 replication origin as strongly as Rts1 RepA and activated the origin in vivo. However, the ori activation was quite inefficient. This study shows that by replacing a small region of P1 RepA with the corresponding region of Rts1 RepA, the efficiency of Rts1 ori activation increased markedly. Interestingly, the same subregion of P1 RepA was found to be important for in vivo activation of the P1 origin. Thus, a region essential for efficient activation of the replication origin was assigned to the P1 RepA molecule as well as to the Rts1 RepA molecule. The region was distinct from a domain necessary for in vitro binding to the origin, although both regions were required for in vivo activation of the respective origin.

Bacteriophage P1↗
PubMed1997

Interaction of P1 RepA with replication origin of plasmid Rts1: capability of an initiator protein inducing replication from a foreign origin.

Rts1 RepA and P1 RepA are trans-acting proteins essential for the initiation of replication of plasmid Rts1 and prophage P1, respectively. In this study, we found that, in vitro, P1 RepA bound to the Rts1 ori fragment and Rts1 incI fragment as strongly as Rts1 RepA. In addition P1 RepA, in trans, activated the Rts1 replication origin that was cloned in pBR322, thus allowing the ori plasmid to be maintained in a polA E. coli host. Under these conditions, however, the ori plasmid was unstable as compared with that when activated by Rts1 RepA. In addition, we found that Rts1 RepA showed no interaction with the P1 replication origin.

Bacteriophage P1↗
PubMed1996

Gene product identification and promoter analysis of hig locus of plasmid Rts1.

The hig (host inhibition of growth) genes of plasmid Rts1 belong to the plasmid-encoded proteic killer gene family. Compared with other proteic killer genes described so far, hig is unique in that the toxic part (higB) exists upstream of the antidote gene (higA). Here we describe results of the promoter analysis of hig genes together with identification of the proteic gene products of higA and higB. Two promoters were identified in the hig locus; a stronger one, named Phig, is located upstream of higB and a weaker one, PhigA, is upstream of higA within the higB coding region. The Phig activity was negatively regulated by HigA and this regulation was augmented by HigB, whereas PhigA was not subjected to such a regulation.

Base Sequence↗
PubMed1996

A new plasmid-encoded proteic killer gene system: cloning, sequencing, and analyzing hig locus of plasmid Rts1.

A new proteic killer gene system, hig, was identified on the plasmid Rts1. The hig locus consisting of a higA and higB is directly related to the temperature sensitive host cell growth conferred by Rts1. We proved that higB encoding presumably a 92-amino-acid polypeptide inhibited segregation of plasmid free cells, and higA encoding a 104-amino-acid polypeptide suppressed the higB function both in cis and in trans.

Amino Acid Sequence↗
PubMed1995

Analysis of functional domains of Rts1 RepA by means of a series of hybrid proteins with P1 RepA.

The RepA protein of the plasmid Rts1, consisting of 288 amino acids, is a trans-acting protein essential for initiation of plasmid replication. To study the functional domains of RepA, hybrid proteins of Rts1 RepA with the RepA initiator protein of plasmid P1 were constructed such that the N-terminal portion was from Rts1 RepA and the C-terminal portion was from P1 RepA. Six hybrid proteins were examined for function. The N-terminal region of Rts1 RepA between amino acid residues 113 and 129 was found to be important for Rts1 ori binding in vitro. For activation of the origin in vivo, an Rts1 RepA subregion between residues 177 and 206 as well as the DNA binding domain was required. None of the hybrid initiator proteins activated the P1 origin. Both in vivo and in vitro studies showed, in addition, that a C-terminal portion of Rts1 RepA was required along with the DNA binding and ori activating domains to achieve autorepression, suggesting that the C-terminal region of Rts1 RepA is involved in dimer formation. A hybrid protein consisting of the N-terminal 145 amino acids of Rts1 and the C-terminal 142 amino acids from P1 showed strong interference with both Rts1 and P1 replication, whereas other hybrid proteins showed no or little effect on P1 replication.

Bacterial Proteins↗
PubMed1994

Mechanism of the cytolytic action of Pseudomonas aeruginosa cytotoxin: oligomerization of the cytotoxin on target membranes.

Pseudomonas aeruginosa cytotoxin (CTX) is thought to be a pore-forming polypeptide of 29 kDa. To study whether CTX assembles into oligomer on target membranes, we solubilized membrane-bound toxin with 1% sodium dodecyl sulfate (SDS) at 25 degrees C and analyzed its molecular size using SDS-polyacrylamide gel electrophoresis and immunoblot analysis. The results indicate that CTX forms a complex of approximately 145 kDa on the surface of erythrocytes and lipid vesicles, and that the complex formation is closely correlated with the toxin-induced permeabilization of target membranes. Thus, CTX may assemble into a pore-forming oligomer on target membranes.

Animals↗
PubMed1994

Cytotoxin-converting phages, phi CTX and PS21, are R pyocin-related phages.

phi CTX is a temperate phage of Pseudomonas aeruginosa harbouring the ctx gene that encodes cytotoxin (CTX). We identified phi CTX as an R pyocin-related phage, by serological and molecular analysis, based on the findings that the infectivity of the phage was inhibited with the antisera directed R pyocins and R pyocin-related phages and that the phi CTX genome showed DNA homology to the genome of PS17 (a representative of the R pyocin-related phages) as well as to the pyocin R2 genes. Another new CTX-converting, R pyocin-related phage named PS21 was isolated from a CTX-producing strain of P. aeruginosa, suggesting the distribution of the ctx gene by certain members of R pyocin-related phage family.

ADP Ribose Transferases↗
PubMed1993

Molecular analysis of a cytotoxin-converting phage, phi CTX, of Pseudomonas aeruginosa: structure of the attP-cos-ctx region and integration into the serine tRNA gene.

The Pseudomonas aeruginosa ctx gene encoding cytotoxin is carried by a temperate phage phi CTX. The genome of phi CTX is a 35.5 kb double-stranded DNA with cohesive ends (cos). It is unique in that the ctx gene and attP site of phi CTX exist very close to the respective cohesive ends. In this study, we determined the structure of this attP-cos-ctx region. The termini of phi CTX are 21-base 5' extended-single-stranded DNAs. The ctx gene is located 361 bp downstream of the left end (cosL). The attP core sequence of 30 bp exists only 647 bp apart from the right end (cosR). The attP-cos-ctx region contains six kinds of repeats and integration host factor-binding sequences and showed sequence-directed static bends, suggesting its potential to form a highly ordered structure. In addition, phi CTX was found to integrate into the serine tRNA gene which was mapped to the 43-45 min region on the P. aeruginosa chromosome.

Amino Acid Sequence↗
PubMed1993

Characteristics of antinociception induced by noncatecholic phenylethylamine derivatives: the involvement of alpha-2-adrenoceptors.

Characteristics of the antinociceptive action of phenylethylamine derivatives, amphetamine, beta-phenylethylamine (PEA) and beta-hydroxyphenylethylamine (OHPEA), were examined. The antinociception induced by PEA derivatives was enhanced by intracisternal injection of norepinephrine or clonidine and attenuated by intracisternal injection of phentolamine or yohimbine, but was not affected by intracisternal injection of prazosin in the mouse hot plate method. PEA derivatives induced a contraction of the rat vas deferens, and this contraction by PEA derivatives was attenuated by the application of phentolamine. The contractions induced by PEA or OHPEA in the reserpinized vas deferens were much smaller than those in the normal one. PEA derivatives inhibited the electrical stimulation-evoked contractions of the vas deferens, and the inhibition by PEA derivatives was reversed by the application of yohimbine. These findings indicate that PEA derivatives may induce the antinociception as a result of stimulating the alpha 2-adrenoceptors. The stimulation of alpha 2-adrenoceptors by PEA derivatives may result from the release of endogenous norepinephrine and/or from direct action on the alpha 2-adrenoceptors.

Adrenergic alpha-Agonists↗
PubMed1992

Isolation and characterization of Shewanella alga from human clinical specimens and emendation of the description of S. alga Simidu et al., 1990, 335.

Genetic and phenotypic studies on the strains biochemically identified as Shewanella putrefaciens, which had a G+C content ranging from 52 to 54 mol% were conducted. The moles percent G+C of the type strain of S. putrefaciens is 46. Surprisingly, DNA homology experiments revealed that all these strains are genetically related to Shewanella alga (which was reported to produce tetrodotoxin), not to the type strain of S. putrefaciens. In this study, we reidentified clinical strains of S. putrefaciens which have a high range of moles percent G+C, as does S. alga. We also characterized the reidentified strains and found that the original description of S. alga (U. Simidu, K. Kita-Tsukamoto, T. Yasumoto, and M. Yotsu, Int. J. Syst. Bacteriol. 40:331-336, 1990) is insufficient to identify this strain. An emended description of S. alga is given.

Animals↗
PubMed1992

Function of the N-terminal half of RepA in activation of Rts1 ori.

The RepA protein of the Rts1 plasmid, consisting of 288 amino acids, is a trans-acting protein essential for replication. A mutant repA gene, repA delta C143, carrying a deletion that removed the 143 C-terminal amino acids of RepA, could transform, but at a low frequency, an Escherichia coli polA strain, JG112, when repA delta C143 was cloned into pBR322 with Rts1 ori in the natural configuration. The transformation was less efficient without the dyad DnaA box in the ori region, and no transformation occurred at 42 degrees C, characteristic of Rts1 replication. A fusion of the 3'-terminal half of repA of the P1 plasmid to repA delta C143 yielded a pBR322 chimeric plasmid that contained Rts1 ori through hybrid (Rts1-P1) repA. This plasmid was maintained much more stably in JG112 at 37 degrees C. At 42 degrees C, however, it was quite unstable. The overproduced hybrid RepA protein showed interference with mini-Rts1 replication in trans and also exhibited an autorepressor function, although both activities were decreased. These findings suggest that the N-terminal half of the RepA molecule of Rts1 is involved in the activation of the replication origin.

Bacterial Proteins↗
PubMed1990

Phage-conversion of cytotoxin production in Pseudomonas aeruginosa.

We isolated a temperate phage which carried the cytotoxin gene (ctx) from a cytotoxin (CTX)-producing Pseudomonas aeruginosa strain, PA158. The phage, phi CTX, had a head with a hexagonal outline and a contractile tail with tail fibres. The phage genome was a linear double-stranded 35.5 kb DNA with single-stranded cohesive ends (cos). The attP, cos and ctx genes were all located very close to one another within a 2.3 kb segment on the phage genome in the order given (in the circular form). phi CTX converted CTX non-producing P. aeruginosa strains into CTX producers. A single copy of phi CTX DNA was integrated at the same site on the host chromosome (attB) in every lysogen, including PA158. However, the amount of CTX produced in these lysogens varied from strain to strain and was less than that in PA158.

Bacteriophages↗
PubMed1990

Effects of mutations in the repA gene of plasmid Rts1 on plasmid replication and autorepressor function.

We constructed a system in which wild-type RepA or RepAcop1 protein was supplied in trans in various amounts to coexisting mini-Rts1 plasmids by clones of the repA or repAcop1 gene under the control of the native promoter with or without its operator sequence. RepAcop1 protein which contains a single amino acid substitution (Arg-142 to Lys) within its 288 amino acids could initiate the replication of the mini-Rts1 plasmid efficiently at both 37 and 42 degrees C even if it was supplied in excess. In contrast, excess wild-type RepA inhibited plasmid replication at 37 degrees C but supported replication at 42 degrees C. Therefore, it appears that the initiator activity of RepA is not related to the incompatibility phenotype associated with an excess of RepA protein. An immunoblot analysis revealed that neither RepA nor RepAcop1 synthesis was temperature sensitive and that both were autogenously regulated to a similar extent because of the presence of an operator located immediately upstream of the promoter. Two mutant RepA proteins, each of which contains a 4-amino-acid insertion in the middle of the protein, maintained the autorepressor and incompatibility activities but lost the ori(Rts1)-activating function.

Ampicillin Resistance↗