Difficulty in early detection of gastric cancer--a case of gastric cancer with metastasis of the liver, peritoneum and intraabdominal lymph nodes.
Explore the source record for details and available documents.
Adenocarcinoma↗
Biomedical subjects
H Niki
Publications and source records attributed to H Niki.
The Escherichia coli FtsH protein is a prokaryotic member of a protein family of putative ATPases involved in membrane functions, cell cycle control, and gene expression.
The ftsH gene is essential for cell viability in Escherichia coli. We cloned and sequenced the wild-type ftsH gene and the temperature-sensitive ftsH1(Ts) gene. It was suggested that FtsH protein was an integral membrane protein of 70.7 kDa (644 amino acid residues) with a putative ATP-binding domain. The ftsH1(Ts) gene was found to have two base substitutions within the coding sequence corresponding to the amino acid substitutions Glu-463 by Lys and Pro-587 by Ala. Homology search revealed that an approximately 200-amino-acid domain, including the putative ATP-binding sequence, is highly homologous (35 to 48% identical) to the domain found in members of a novel, eukaryotic family of putative ATPases, e.g., Sec18p, Pas1p, CDC48p, and TBP-1, which function in protein transport pathways, peroxisome assembly, cell division cycle, and gene expression, respectively. Possible implications of these observations are discussed.
ATP-Dependent Proteases↗
Topology and subcellular localization of FtsH protein in Escherichia coli.
FtsH protein in Escherichia coli is an essential protein of 70.7 kDa (644 amino acid residues) with a putative ATP-binding sequence. Western blots (immunoblots) of proteins from fractionated cell extracts and immunoelectron microscopy of the FtsH-overproducing strain showed exclusive localization of the FtsH protein in the cytoplasmic membrane. Most of the FtsH-specific labeling with gold particles was observed in the cytoplasmic membrane and the adjacent cytoplasm; much less was observed in the outer membrane and in the bulk cytoplasm. Genetic analysis by TnphoA insertions into ftsH revealed that the 25- to 95-amino-acid region, which is flanked by two hydrophobic stretchs, protrudes into the periplasmic space. From these results, we concluded that FtsH protein is an integral cytoplasmic membrane protein spanning the membrane twice and that it has a large cytoplasmic carboxy-terminal part with a putative ATP-binding domain. The average number of FtsH molecules per cell was estimated to be approximately 400.
ATP-Dependent Proteases↗
E.coli MukB protein involved in chromosome partition forms a homodimer with a rod-and-hinge structure having DNA binding and ATP/GTP binding activities.
mukB mutants of Escherichia coli are defective in the correct partitioning of replicated chromosomes. This results in the appearance of normal-sized anucleate (chromosome-less) cells during cell proliferation. Based on the nucleotide sequence of the mukB gene, the MukB protein of 177 kDa was predicted to be a filamentous protein with globular domains at the ends, and also having DNA binding and nucleotide binding abilities. Here we present evidence that the purified MukB protein possesses these characteristics. MukB forms a homodimer with a rod-and-hinge structure having a pair of large, C-terminal globular domains at one end and a pair of small, N-terminal globular domains at the opposite end; it tends to bend at a middle hinge site of the rod section. Chromatography in a DNA-cellulose column and the gel retardation assay revealed that MukB possesses DNA binding activity. Photoaffinity cross-linking experiments showed that MukB binds to ATP and GTP in the presence of Zn2+. Throughout the purification steps, acyl carrier protein was co-purified with MukB.
Acyl Carrier Protein↗
Characterization of high molecular weights of complexes and polymers of cytoplasmic proteins in Escherichia coli.
To search for filamentous polymers of cytoplasmic proteins of Escherichia coli, high molecular weights (> 670 kDa) of protein complexes of cell extracts were fractionated by gel filtration and ion-exchange column chromatography. Proteins of 100, 77 and 52 kDa were co-purified. The 100- and 52-kDa proteins were identified to be pyruvate dehydrogenase and lipoamide dehydrogenase, respectively, by determining the N-terminal amino acid sequences. Experimental results indicate that the 77-kDa protein is identical to dihydrolipoamide acyltransferase. The 100-kDa protein was found to be identical to the 100-kDa protein described by Tomioka (1991), and was related to the formation of filaments and sheets in the presence of 100 mM KCl. However, neither long filaments nor sheets were observed in our sample containing these enzymes, which was not consistent with Tomioka's conclusion. Another 100-kDa protein which forms spirosome-like particles was purified and identified to be alcohol dehydrogenase based on the N-terminal sequence.
Acyltransferases↗
Identification and characterization of the smbA gene, a suppressor of the mukB null mutant of Escherichia coli.
The mukB gene encodes a protein involved in chromosome partitioning in Escherichia coli. To study the function of this protein, we isolated from the temperature-sensitive mukB null mutant and characterized 56 suppressor mutants which could grow at 42 degrees C. Ten of the mutants also showed cold-sensitive growth at 22 degrees C. Using one of the cold-sensitive mutants as host, the wild type of the suppressor gene was cloned. The cloned suppressor gene complemented all of the 56 suppressor mutations. DNA sequencing revealed the presence of an open reading frame of 723 bp which could encode a protein of 25,953 Da. The gene product was indeed detected. The previously undiscovered gene, named smbA (suppressor of mukB), is located at 4 min on the E. coli chromosome, between the tsf and frr genes. The smbA gene is essential for cell proliferation in the range from 22 to 42 degrees C. Cells which lacked the SmbA protein ceased macromolecular synthesis. The smbA mutants are sensitive to a detergent, sodium dodecyl sulfate, and they show a novel morphological phenotype under nonpermissive conditions, suggesting a defect in specific membrane sites.
Amino Acid Sequence↗
Escherichia coli mutant Y16 is a double mutant carrying thermosensitive ftsH and ftsI mutations.
The Escherichia coli mutant Y16, which shows thermosensitive colony formation and filamentation with reduced amounts of penicillin-binding protein 3 (PBP3), has mutations in the ftsI gene encoding PBP3 and in the ftsH gene. The ftsI mutation markedly reduces the amount of PBP3 at 42 degrees C, whereas the amount of the ftsH single mutant is slightly reduced.
Bacterial Proteins↗
Lupus nephritis associated with bacterial panperitonitis and lung alveolar hemorrhage.
A 36-year-old woman was admitted to the hospital with the diagnosis of nephrotic syndrome due to lupus nephritis. The patient had panperitonitis caused by Staphylococcus aureus as a complication, and an emergency laparotomy was performed. After the operation, the patient developed a massive lung alveolar hemorrhage. Methylprednisolone pulse therapy showed a marked effect on the lung hemorrhage. It is known that lung alveolar hemorrhages associated with systemic lupus erythematosus have a very high mortality; the present case is relatively rare because of the good response to steroid pulse therapy.
Adult↗
The new gene mukB codes for a 177 kd protein with coiled-coil domains involved in chromosome partitioning of E. coli.
An Escherichia coli temperature sensitive mutant which produces spontaneously normal size anucleate cells at low temperature was isolated. The mutant is defective in a previously undescribed gene, named mukB, located at 21 min on the chromosome. The mukB gene codes for a large protein (approximately 180 kd). A 1534 amino acid protein (176,826 daltons) was deduced from the nucleotide sequence of the mukB gene. Computer analysis revealed that the predicted MukB protein has distinct domains: an amino-terminal globular domain containing a nucleotide binding sequence, a central region containing two alpha-helical coiled-coil domains and one globular domain, and a carboxyl-terminal globular domain which is rich in Cys, Arg and Lys. A 180 kd protein detected in wild-type cell extracts by electrophoresis is absent in mukB null mutants. Although the null mutants are not lethal at low temperature, the absence of MukB leads to aberrant chromosome partitioning. At high temperature the mukB null mutants cannot form colonies and many nucleoids are distributed irregularly along elongated cells. We conclude that the MukB protein is required for chromosome partitioning in E. coli.
Amino Acid Sequence↗
Chlamydia infections in Kawasaki disease.
Explore the source record for details and available documents.
Bacteriuria↗
Partitioning of a mini-F plasmid into anucleate cells of the mukB null mutant.
The partition-proficient mini-F plasmid pXX325 was stably maintained in the mukB null mutant, which is defective in chromosome partitioning into the two daughter cells. In the null mutant, the plasmid was partitioned into both nucleate and anucleate daughter cells, independently of host chromosomes.
Azlocillin↗
Eosinophilic peritonitis responding to treatment with glycyrrhizin.
A 63-year-old man with diabetes mellitus for 15 years was admitted to our hospital in 1990 because of end-stage renal failure. Five days after beginning continuous ambulatory peritoneal dialysis (CAPD) he developed an eosinophilic peritonitis (EP). With protein loss in the dialysate and a decreased serum albumin level, the patient developed ankle edema. The patient was treated with glycyrrhizin, and his EP resolved. It is suggested that an allergic background may play an important role in the development of EP in patients on CAPD.
Anti-Inflammatory Agents, Non-Steroidal↗
New topoisomerase essential for chromosome segregation in E. coli.
The nucleotide sequence of the parC gene essential for chromosome partition in E. coli was determined. The deduced amino acid sequence was homologous to that of the A subunit of gyrase. We found another new gene coding for about 70 kd protein. The gene was sequenced, and the deduced amino acid sequence revealed that the gene product was homologous to the gyrase B subunit. Mutants of this gene were isolated and showed the typical Par phenotype at nonpermissive temperature; thus the gene was named parE. Enhanced relaxation activity of supercoiled plasmid molecules was detected in the combined crude cell lysates prepared from the ParC and ParE overproducers. A topA mutation defective in topoisomerase I could be compensated by increasing both the parC and the parE gene dosage. It is suggested that the parC and parE genes code for the subunits of a new topoisomerase, named topo IV.
Amino Acid Sequence↗
Nucleotide sequence of the tolC gene of Escherichia coli.
Explore the source record for details and available documents.
Amino Acid Sequence↗
Linear multimer formation of plasmid DNA in Escherichia coli hopE (recD) mutants.
The hopE mutants of Escherichia coli, which cannot stably maintain a mini-F plasmid during cell division, have mutations in the recD gene coding for subunit D of the RecBCD enzyme (exonuclease V). A large amount of linear multimer DNA of mini-F and pBR322 plasmid accumulates in these hopE mutants. The linear multimers of plasmid DNA in the hopE (recD) mutants accumulate in sbc+ genetic backgrounds and this depends on the recA+ gene function. Linear plasmid multimers also accumulated in a recBC xthA triple mutant, but not an isogenic xth A mutant or an isogenic recBC mutant. The recBC xth A mutant is defective in the conjugative type of recombination. Linear plasmid multimers were not detected in the recBC strain. We propose models to account for linear multimer formation of plasmids in various mutants.
Chromosome Mapping↗
Maintenance of plasmids in HU and IHF mutants of Escherichia coli.
Complementation and sequencing analyses revealed that the hopD mutants, which could not support stable maintenance of mini-F plasmids (Niki et al. 1988), had mutations in the hupB gene, and that the hopD410 mutation was an ochre mutation at the 5th Gln position of HU-1. Maintenance and stability of various plasmids, mini-P1 plasmids, mini-F plasmids, and oriC plasmids, were studied in the hupA and hupB mutants (HU mutants), and himA and hip mutants (IHF mutants). Mini-P1 plasmids and mini-F plasmids could not be introduced into the delta hupA-delta hupB double deletion mutant. Replication of mini-F plasmids was partially inhibited in the hupB mutants, including the delta hupB and hopD(hupB) mutants, whereas replication of oriC plasmids was not significantly affected even in the delta hupA-delta hupB double deletion mutant. The mini-P1 plasmid was slightly unstable in the himA-hip mutant, whereas the mini-F plasmid was stable.
Amino Acid Sequence↗
Positioning of replicated chromosomes in Escherichia coli.
The positioning of replicated chromosomes at one-fourth and three-fourths of the cell length was inhibited when protein synthesis was inhibited by chloramphenicol or rifampin or by starvation for amino acids. Under these conditions, the progress of chromosome replication continued and replicated chromosomes were located close to each other as one nucleoid mass at midcell. Cells which already had two separate daughter chromosomes located at the cell quarters divided into two daughter cells under these conditions. When protein synthesis resumed, daughter chromosomes moved from midcell to the cell quarters, respectively, before any detectable increase in cell length was observed. The chromosome positioning occurred even under inhibition of the initiation of chromosome replication and under inactivation of DNA gyrase. The chromosome positioning presumably requires new synthesis of a particular protein(s) or translation itself.
Chloramphenicol↗
Identification and characterization of gyrB mutants of Escherichia coli that are defective in partitioning of mini-F plasmids.
hopA mutants, which have been suggested to be defective in mini-F plasmid partitioning (H. Niki, C. Ichinose, T. Ogura, H. Mori, M. Morita, M. Hasegawa, N. Kusukawa, and S. Hiraga, J. Bacteriol. 170:5272-5278, 1988), were found to carry mutations in the gyrB gene, coding for the B subunit of DNA gyrase. In gyrB(HopA) mutants, relaxation of the superhelicity of plasmids, increased IncG incompatibility, and increased SopB protein production were observed. It is suggested that altered expression of the sop genes, which is due to relaxation of the mini-F plasmid DNA, causes both defective partitioning of the mini-F plasmids and increased IncG incompatibility in gyrB(HopA) mutants.
Amino Acid Sequence↗