Search PubMed⌕ Search

Biomedical subjects

S Horikawa

Publications and source records attributed to S Horikawa.

At least 91 records · Page 5Linked to original sources
PubMed1980

Cell-free translation and regulation of Candida lipolytica acetyl-coenzyme-A carboxylase messenger RNA.

Messenger RNA from Candida lipolytica directs the synthesis of complete acetyl-coenzyme-A carboxylase in the mRNA-dependent reticulocyte lysate cell-free translation system. The identity of the translation product is evidenced by the following results: first, it is immunoprecipitated with antibody to acetyl-CoA carboxylase and competes with authentic acetyl-CoA carboxylase for binding to the antibody; secondly, it co-migrates with authentic acetyl-CoA carboxylase (Mr 230000) upon dodecylsulfate/polyacrylamide gel electrophoresis; finally, the peptide fragments formed by its partial proteolysis with papain or alpha-chymotrypsin are identical with those formed from authentic acetyl-CoA carboxylase. With the use of this assay system, it has been demonstrated that the level of acetyl-CoA carboxylase mRNA activity in C. lipolytica cells decreases with increasing concentrations of oleic acid in culture medium and that the changes in the mRNA activity parallel those in the cellular level of acetyl-CoA carboxylase. This finding, in conjunction with our previous study, indicates that the diminished synthesis of acetyl-CoA carboxylase in cells grown in the presence of fatty acid is due to a reduced level of the mRNA coding for the enzyme.

Acetyl-CoA Carboxylase↗
PubMed1980

Penicillin-binding proteins of Streptomyces cacaoi, Streptomyces olivaceus, and Streptomyces clavuligerus.

Penicillin-binding proteins of three Streptomyces strains, S. cacaoi, S. olivaceus, and S. clavuligerus, were examined by gel electrophoresis and fluorography. In a beta-lactamase producer, S. cacaoi, at least five membrane-bound penicillin-binding proteins were detected, but in two beta-lactam producers, S. olivaceus and S. clavuligerus, fewer penicillin-binding proteins were detected. Mecillinam and methicillin bound selectively to some penicillin-binding proteins in S. cacaoi, whereas they did not bind at all to those in S. olivaceus and S. clavuligerus. Clavulanic acid bound to penicillin-binding proteins only at a very high concentration in S. cacoi. This compound did not bind to those of S. olivaceus and S. clavuligerus. Penicillin-binding proteins in culture supernatant and cytoplasm and minimum inhibitory concentrations of these strains against benzylpenicillin were also examined.

Amdinocillin↗
PubMed1980

Penicillin-binding proteins in Streptomyces cacaoi and Streptomyces clavuligerus. Kinetics of [13C]benzylpenicillin binding, temperature sensitivity and release of [14C]benzylpenicillin from the complex.

On the membrane-bound penicillin-binding proteins (PBP) of Streptomyces cacaoi and S. clavuligerus, the kinetics of [14C]benzylpenicillin binding, the temperature sensitivity, the release of [14C]benzylpenicillin from the [14C]benzylpenicillin-PBP complexes and the changes of the PBP patterns during the growth cycle were examined. All the PBP in both strains, especially PBP in S. clavuligerus, had very low affinity for benzylpenicillin, comparing with other bacteria. As for the temperature sensitivity of the binding ability, all the PBP in S. cacaoi were highly sensitive to heat, while PBP-3 in S. clavuligerus retained the binding activity after incubation at 60 degrees C for 10 minutes. The release of [14C]benzylpenicillin from the complexes with PBP-1, PBP-2 in S. cacaoi and PBP-3 in S. clavuligerus was relatively fast initially. However, this soon reached a plateau and the complexes retained [14C]benzylpenicillin even after prolonged incubation. During the growth cycle, the PBP patterns in S. cacaoi did not change significantly. However, in S. clavuligerus, a band of molecular weight of about 120,000 daltons was observed only in the membrane fraction of early log phase, and PBP-1 (Mr=83,000) and PBP-2 (Mr=79,000) appeared only slightly in this phase.

Bacterial Proteins↗
PubMed1980

Penicillin-binding proteins in Bacillus subtilis. The effects on penicillin-binding proteins and the antibacterial activities of beta-lactams.

Several beta-lactams were investigated on the affinity for the penicillin-binding proteins (PBPs) and the antibacterial activity in Bacillus subtilis. The beta-lactams such as ampicillin, PS-5, methicillin and SCE-963, which had high affinities for PBP-2 showed strong antibacterial activities and the beta-lactams such as cephamycin C, Y-G19Z-GG and Y-G19Z-G, which had high affinities for PBP-1 but low affinities for PBP-2, showed weak antibacterial activities. Clavulanic acid and nocardicin A, which had almost no affinities for all the PBPs detected, showed very low antibacterial activities. These results suggest that PBP-2 in Bacillus subtilis is the lethal target of these beta-lactam antibiotics.

Bacillus subtilis↗
PubMed1980

[Transhepatic biliary drainage as a method in the diagnosis and treatment of obstructive jaundice].

Percutaneous transhepatic biliary drainage was performed on eleven jaundiced patients, who had obstruction of the bile duct, in order to determine the exact site and nature of the obstruction and to alleviate the jaundice. In the present series, six patients were treated with external biliary drainage. Four of them received this treatment prior to radical surgery. In the remaining two cases the external drainage was a palliative procedure. In five patients, the drainage catheter was internalized through the obstructed bile duct (internal biliary drainage). One of these patients was subsequently treated with radical surgery. In two cases, the internal biliary drainage was palliative. In the two remaining cases, intraluminal selective irradiation was introduced via Iridium 192 flexible wires. Severe hemobilia occurred in one patient, who was successfully treated by lithotomy and "T" tube drainage. We conclude that the simplicity and low cost of these drainage procedures recommend them as extremely useful for the diagnosis and treatment of obstructive jaundiced patients.

Adult↗
PubMed1980

Penicillin-binding proteins in Streptomyces cacaoi. The effects on penicillin-binding proteins and the antibacterial activities of beta-lactams.

Penicillin-binding proteins (PBPs) in membrane of Streptomyces cacaoi were investigated by sodium dodecylsulfate-polyacrylamide gel electrophoresis-fluorography. At the same time, eleven beta-lactams were examined on the affinities for these PBPs and the antibacterial activities against S. cacaoi, comparing with those in Bacillus subtilis reported in the preceding paper. The affinity patterns of beta-lactams for PBPs both in S. cacaoi and B. subtilis were similar in many points. Here again, the grouping of beta-lactams based on the affinity for PBP-2 (M. W., 91,000) was in accord with that based on the antibacterial activity. These results suggest that among PBPs detected in S. cacaoi, PBP-2 is the most likely target of killing by these beta-lactam antibiotics.

Bacterial Proteins↗
PubMed1979

Individual variations in the effects of flurazepam, clorazepate, L-dopa and thyrotropin-releasing hormone on REM sleep in man.

The comporative effects of flurazepam, clorazepate, L-dopa, and thyrotropin-releasing hormone (TRH) on REM sleep were investigated in normal, healthy adults. A single dose of each drug was given orally to the subjects 30 min before bedtime. A dose of 30 mg flurazepam significantly decreased REM sleep-time when compared to the mean baseline record. No change was noted in REM sleep-time on the clorazepate (15 mg) night, L-dopa (1000 mg) night, or TRH (2 mg) night, when compared to the mean baseline record. Because large individual variations were found in REM sleep time on each drug night, and in percentage increase in REM sleep following partial differential REM deprivation (PDRD), correlation was investigated between them. The percentage decrease in REM sleep during flurazepam was found to have a significant negative correlation with the percentage increase in REM sleep after PDRD in individual subjects. Although there was no significant change in REM sleep on TRH night when compared to the mean baseline record, a similar significant negative correlation was noted. On the L-dopa night, there was a tendency toward a negative correlation between them. No significant correlation was noted on the clorazepate night.

Adult↗
PubMed1979

Purification of beta-lactamase from Streptomyces cellulosae by affinity chromatography on Blue Sepharose.

A beta-lactamase from culture supernatant of Streptomyces cellulosae was purified about 1,450-fold to apparent homogeneity in polyacrylamide gel electrophoresis and isoelectric focusing on polyacrylamide gel sheet. The methods used were ammonium sulfate precipitation, CM-52 cellulose ion-exchange chromatography and affinity chromatography on Blue Sepharose CL-6B. The molecular weight was determined to be approximately 27,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This value was in good agreement with the previous value determined by gel filtration on Sephadex G-75. The isoelectric point was pH 9.5. The enzyme behaved primarily as penicillinase and apparent Km value for benzylpenicillin was 500 microM. The beta-lactamase of S. cellulosae interacted strongly with blue dextran and NADP+-agarose but not with Sepharose. In addition, the presence of NADP+ but not NAD+ and ATP diminished sharply the intrinsic fluorescence intensity of the enzyme and the apparent association constant was calculated to be 1.4 x 10(3) M-1. The beta-lactamase decreases its enzymatic activity against benzylpenicillin in the presence of NADP+. From these results, it is suggested that this beta-lactamase has a dinucleotide binding fold.

Amino Acids↗
PubMed1978

Production and property of beta-lactamases in Streptomyces: comparison of the strains isolated newly and thirty years ago.

Productivity and property of beta-lactamases of Streptomyces strains isolated from soil some 30 years ago were studied in comparison with those of the newly isolated strains. At least three-quarters of the Streptomyces strains produced beta-lactamase constitutively and extracellularly, mainly as penicillinases, as in the cases of those from the newly isolated strains. Strains such as S. albus, S. diastatochromogenes, S. fradiae, and S. lavendulae were the highest producing strains, and the amounts of beta-lactamase activity they produced were comparable to those produced by Bacillus cereus 569/H and B. licheniformis 749/C. In isoelectric focusing, most strains contained one main beta-lactamase band with a number of satellite bands, but some strains contained one band only. Although beta-lactamases from most strains showed isoelectric points of pH 5 to 6, some strains produced beta-lactamases with strongly basic isoelectric points of pH 8 to 9. Molecular weights were between 20,000 and 30,000. From these results, it is suggested that the proportion of the producing strains of Streptomyces and the properties of the beta-lactamases have not been affected significantly by the introduction of penicillin into the natural environment, in contrast to the cases of other microorganisms.

Amidohydrolases↗
PubMed1978

Membrane-bound penicillin-binding proteins of Escherichia coli. Comparison of a strain carrying an R-factor and the parent strain.

Membrane-bound penicillin-binding proteins of an Escherichia coli carrying an R factor which mediated the resistance to penicillins were examined by slab gel electrophoresis and fluorography using beta-lactamase inhibitors such as methicillin, clavulanic acid and MC-696-SY2-A, and by affinity chomatography. By fluorography, it appeared that the penicillin-binding proteins of the strain carrying the R factor could not be distinguished from those of the parent strain. In both strains, methicillin had a preferential affinity for penicillin-binding proteins 2 and 3, clavulanic acid for 2 and 4, and MC-696-SY2-A for 1A at the concentration which was needed to inhibit about 75 approximately 80% of beta-lactamase activity of the membrane fraction from a strain carrying an R factor. This with other facts indicates that MC-696-SY2-A has a unique character in the binding to penicillin-binding proteins. By affinity chromatography using cephalexin-CH-Sepharose 4B column, two major cephalexin-binding proteins were detected. Their molecular weights were found to be 110,000 and 32,000, respectively. These two proteins correpsonded to penicillin-binding proteins 1 and 5/6. From these results it was suggested that the R factor had no influence on the penicillin-binding proteins in the E. coli strain examined.

Bacterial Proteins↗
PubMed1978

A role of anti-"LD" antibody in induction of active enhancement in rat heart allografts.

Heart allografts from S-D to Wistar rats pretreated with 5 x 10(7) spleen cells taken from donor strain 1 or 2 weeks before, survived indefinitely. Sera taken from the pretreated rats showed high lymphocytotoxic titers and obvious blocking activity against LMC of immunized Wistar spleen cells. Even though the sera were exhaustively absorbed with RBC, this blocking activity was not impaired, although CDC was reduced. The active prolongation of graft survival, therefore, correlates with the presence of anti-LD antibody.

Animals↗
PubMed1976

Dietary and hormonal regulation of the content of acetyl coenzyme A carboxylase-synthesizing polysomes in rat liver.

Specific polysomes involved the the synthesis of acetyl-CoA carboxylase [acetyl-CoA: carbon-dioxide ligase (ADP-forming), EC 6.4.1.2] have been identified by the binding of 125I-labeled antiacetyl-CoA carboxylase to rat liver polysomes. The binding is highly specific and occurs through the recognition of the nascent peptide chains on polysomes. With the use of the 125I-labeled antibody binding technique, it has been demonstrated that the relative content of acetyl-CoA carboxylase-synthesizing polysomes in the liver correlates well with the rate of hepatic synthesis of the enzyme in rats subjected to different dietary conditions as well as in alloxan-diabetic rats with or without insulin treatment.

Acetyl-CoA Carboxylase↗
PubMed1975

Effects of thienodiazepine derivatives on human sleep as compared to those of benzodiazepine derivatives.

The effects of new thienodiazepine derivatives, such as clotiazepam and Y-7131, on normal human sleep were investigated on 5 subjects and compared to those of benzodiazepine derivatives, such as diazepam and nitrazepam. REM sleep was significantly decreased only with 2 mg of Y-7131 and rebound elevation of REM sleep did not follow in recovery 1 and 2 nights. By using partial differential REM deprivation which was designed by us, there was also no rebound elevation of REM sleep noted in recovery 2 nights following 2 mg of Y-7131 medication. REM sleep was not suppressed with 15 mg of clotiazepam, 6 mg of diazepam and 10 mg of nitrazepam when compared to the baseline night. With regard to NREM sleep, stage 2 was significantly increased with 15 mg of clotiazepam and 10 mg of nitrazepam, but stage SWS was significantly decreased with 10 mg of nitrazepam.

Adult↗