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Biomedical subjects

K Kitano

Publications and source records attributed to K Kitano.

At least 163 records · Page 9Linked to original sources
PubMed1986

Transglycosylase and endopeptidase participate in the degradation of murein during autolysis of Escherichia coli.

The cell wall degradation products released from Escherichia coli during autolysis triggered by cephaloridine or trichloroacetic acid were isolated and characterized. Murein was selectively lost from the disaccharide tetrapeptides and the bisdisaccharide tetrapeptide components. Two major autolytic products accounted for more than 85% of the released material. Compound 1 (60 to 80% of released material) was a disaccharide tetrapeptide monomer containing a 1,6-anhydromuramic acid residue. Compound 2 (15 to 30% of released material) was a mixture of a tritripeptide and a tritetrapeptide without hexosamines. Taken together the findings suggest that autolytic cell wall degradation in E. coli is selective and involves the activity of both the hydrolytic transglycosylase and an endopeptidase. Upon release, at least some of the wall components were also exposed to the activity of the N-acetylmuramic acid-L-alanine amidase.

Amidohydrolases↗
PubMed1986

An NMR study on the structure of OR3 in the lambda cro-OR3 complex.

1H-NMR spectra of lambda-OR3 17mer in the complex with lambda-cro has been analysed and the change in its conformation on the complexation has been deduced. The changed conformation is retained until the duplex melts above 55 degrees C. Increase in heat stability of the cro dimer was observed. The result was compared with those of other DNA fragments phi 80-OR2 19 mer and the CRP binding site 22mer mixed with lambda-cro.

Amino Acid Sequence↗
PubMed1986

Characterization of recombinant cDNA clones for canine cardiac phospholamban.

Complementary DNA clones specific for phospholamban have been isolated from a canine cardiac cDNA library. The amino acid sequence deduced from the cDNA sequence showed that phospholamban consisted of 52 amino acid residues and was synthesized without an amino-terminal signal sequence. The RNA blot analysis revealed that phospholamban mRNAs were represented by two main species of approximately 1.2kb and approximately 2.8kb. These mRNAs appeared to differ primarily in the length of the 3' untranslated region.

Amino Acid Sequence↗
PubMed1985

Photo CIDNP study on the complex formation of lambda cro protein with OR3.

A photo CIDNP spectrum of lambda cro repressor protein showed that one of the three tyrosines and His 35 are quite accessible to the photosensitive dye. For the remaining two tyrosine residues one is slightly accessible, but the other is inaccessible. In comparison with the result of differential nitration at tyrosine side chains followed by the peptide analysis, it can be concluded that Tyr 26 is mostly exposed and Tyr 51 is slightly exposed on the surface of the cro dimer. On the addition of OR3 17mer, His 35 and Tyr 26 are no longer accessible to the dye, which indicates that they are involved in interaction. However, a similar phenomenon was observed by adding CAP binding site 22mer. The interaction mechanism will be discussed.

Bacteriophage lambda↗
PubMed1985

Dynamic behavior of the imino protons of the gamma OR3 17mer in H2O solution studied by high-resolution NMR.

The imino proton resonances of gamma OR3 17mer in water were observed at 500 MHz with the time-shared Redfield pulse train. All of the 17 imino proton resonances could be assigned specifically to individual base pairs by utilizing the trace of NOE connectivities between the imino and adenine C2H protons and between imino protons themselves. AT1 and 17 showed abnormally high chemical shifts in comparison with the other AT pairs. On raising the temperature, broadening of the signal occurred in a sequential manner from the terminals except for AT10 and AT11, which were broadened at a lower temperature than GC12. The relaxation rates of the imino protons were measured by the inversion recovery method. The rates at higher temperatures represent the exchange rates of the imino protons. From the temperature dependences, activation energies of about 15 kcal/mol for the AT imino protons and 23-26 kcal/mol for the GC imino protons were obtained.

Bacteriophage lambda↗
PubMed1985

[Cerebral venous thrombosis with familial antithrombin III deficiency].

A case of cerebral venous thrombosis with familial antithrombin III (AT III) deficiency was reported and we discussed the anticoagulant therapy of cerebral venous thrombosis from the viewpoint of AT III. The patient, a 17-year-old boy, was admitted to our clinic with severe bifrontal headache, generalized convulsions and progressive disturbance of consciousness. He developed deep vein thrombosis in his right leg and pulmonary emboli two years earlier when he was placed on heparin and so forth, followed by warfarin sodium. Warfarin was terminated 9 months prior to his recent illness. On neurological examination on admission, he was semicomatous with blurred disc margins, roving eye movements with right abducens nerve palsy, nuchal stiffness and right flaccid hemiplegia. Left carotid angiogram and CT scan revealed extensive superior sagittal sinus thrombosis, complicated with hemorrhagic infarcts in bilateral frontal lobes. When examined for coagulation studies, the patient and his father had decrease in AT III activity and antigen levels. He was treated successfully with antiedematous agents and anticonvulsants during acute phase of illness. He was thereafter placed on warfarin 5-6 mg/day with no further clinical thromboembolic event for 2 years 9 months. There was no neurological abnormality when he was last examined, although he was treated with valproic acid 1,200 mg/day and phenytoin 250 mg/day to control occasional adversive seizures. A coagulation study following infusion of 5,000 units of AT III was carried out. Warfarin was discontinued the day before the study. 0.64 U/kg of AT III administration resulted in a 1% increase in AT III level after the infusion. The biological half life of AT III was 14.4 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

Synthesis of a gene for human growth hormone and its expression in Escherichia coli.

A gene coding for human growth hormone, which consists of 192 amino acids, was chemically synthesized. The synthesis entailed ligating 78 deoxyribooligonucleotides, which had been synthesized on polymer supports by the phosphotriester method with frequently occurring amino acid codons of Escherichia coli. The chemically synthesized gene was inserted into an E. coli plasmid downstream from the E. coli trp promoter, with a modified ribosome-binding region carried on pBR322. E. coli cells transformed with this recombinant plasmid synthesized 2.9 X 10(6) molecules per cell of human growth hormone upon induction. The induced polypeptide was identical with natural human growth hormone in size and in immunological properties, as well as in biological activity as examined by the tibial test with hypophysectomized rats.

Amino Acid Sequence↗
PubMed1984

Structure-activity relations of 5,6-cis carbapenem antibiotics and role of factors determining susceptibility of Escherichia coli to beta-lactam antibiotics.

The antibacterial activities of twelve 5,6-cis carbapenem antibiotics, including four semisynthetic derivatives of C-19393 H2 and S2, against 15 microorganisms were examined, and their structure-activity relations are discussed in relation to minimum inhibitory concentrations against Staphylococcus aureus and Escherichia coli as a Gram-positive and a Gram-negative standard strain, respectively. The contribution of chromosomal beta-lactamase (amp C), permeability barrier, and penicillin-binding protein (PBP) 1B to the resistance of E. coli to these carbapenem antibiotics was examined using mutants lacking each of these cellular components. The beta-lactamase was not involved in the resistance. These antibiotics easily permeated the outer membrane. A PBP 1B-defective mutant was supersensitive to these carbapenem antibiotics and to other types of beta-lactam antibiotics.

Anti-Bacterial Agents↗
PubMed1983

Behavior of the imino protons of the lambda OR3 17mer studied by high resolution NMR.

Imino proton resonances of lambda OR3 17mer were observed with time-shared Redfield pulse method by using a JEOL 500 MHz NMR instrument. They show gradual broadening and disappearance with the elevation of temperature indicating the stepwise melting of the duplex. By the selective irradiation at each peak position nuclear Overhauser effects were observed between the imino and adenine C2H protons and between imino protons themselves. Combining these data, fifteen imino proton resonances could be assigned to each base pair except two terminal AT base pairs. Based on the assignment it can be said that AT rich regions near the terminal melt first, followed by the melting of the inside GC rich core. The two AT base pairs in the middle of the GC core are resistant to heat. Spin lattice relaxation times were also observed and the results are consistent with the melting profile.

Bacteriophage lambda↗
PubMed1983

The synthesis of human growth hormone gene.

Human growth hormone gene with 584 base pairs has been synthesized by joining with DNA ligase of chemically synthesized deoxyoligonucleotides with the chain length of 15-25. The phosphotriester polymer support synthesis was employed to obtain 80 oligonucleotides.

Base Sequence↗
PubMed1982

C-19393 E5, a new carbapenem antibiotic. Fermentation, isolation and structure.

A new carbapenem antibiotic, C-19393 E5, was isolated from the culture filtrate of Streptomyces griseus subsp. cryophilus C-19393 as a minor component. The chemical structure of the antibiotic was determined by comparing its spectral data with those of the known 5,6-cis carbapenem antibiotics and confirmed by partial synthesis from epithienamycin B as shown in Fig. 1. The antibiotic has a broad antimicrobial spectrum and shows strong inhibitory activity against beta-lactamases.

Anti-Bacterial Agents↗