PubMed Health⌕ Search

Biomedical subjects

F Fukui

Publications and source records attributed to F Fukui.

At least 19 recordsLinked to original sources
PubMed2002

Study on social responses (encouraging public awareness) to sudden infant death syndrome: evaluation of SIDS prevention campaigns.

The sudden infant death syndrome (SIDS) prevention campaign promulgated by the SIDS Family Associations was initiated and directed to medical professionals in 1996 and to mothers in 1997. In mid-1998, the Ministry of Health and Welfare began to support this campaign. In parallel with these moves and with cooperation from the study group of the Ministry of Health and Welfare and the SIDS Family Associations of Japan, a Japanese segment of the International Child Care Practices Survey (ICCPS) was conducted in two phases--from 1996 to 1997 and from 1998 to 1999--to observe the trends in risk factors for SIDS that may exist in the child rearing environment in Japan. Consequently, after the SIDS prevention campaign, the risk factors for SIDS, such as the practice of placing infants in a prone posture, smoking, and formula feeding, were reduced. Correspondingly, it was shown that the incidence of SIDS in Japan and in Kanagawa Prefecture where the survey was carried out considerably decreased (0.42-0.24 per 1000 live births). These data indicate that this prevention campaign has been effective.

Health Education↗
PubMed2001

Enhancement of learning capacity and cholinergic synaptic function by carnitine in aging rats.

The effects of a carnitine derivative, acetyl-L-carnitine (ALCAR), on the cognitive and cholinergic activities of aging rats were examined. Rats were given ALCAR (100 mg/kg) per os for 3 months and were subjected to the Hebb-Williams tasks and a new maze task, AKON-1, to assess their learning capacity. The learning capacity of the ALCAR-treated group was superior to that of the control. Cholinergic activities were determined with synaptosomes isolated from the cortices. The high-affinity choline uptake by synaptosomes, acetylcholine synthesis in synaptosomes, and acetylcholine release from synaptosomes on membrane depolarization were all enhanced in the ALCAR group. This study indicates that chronic administration of ALCAR increases cholinergic synaptic transmission and consequently enhances learning capacity as a cognitive function in aging rats.

Acetylcarnitine↗
PubMed2001

Purification and characterization of maltose phosphorylase from Bacillus sp. RK-1.

Bacillus sp. RK-1 was isolated as a bacterium that produced maltose phosphorylase (MPase) in the culture supernatant. Screening was done from among about 400 isolates that could grow at 55 degrees C in a medium containing maltose as the sole carbon source. The enzyme was purified to an electrophoretically homogeneous state and some properties were investigated. The Mr of the enzyme was estimated to be 170 kDa by gel filtration and 88.5 kDa by SDS-PAGE, suggesting that it consisted of two identical subunits. The enzyme showed optimum activity around pH 6.0-7.0 and the optimum temperature was about 65 degrees C. The enzyme was stable in the range of pH 5.5-8.0 after keeping it at 4 degrees C for 24 h and retained the activity up to about 55 degrees C after keeping it for 15 min. This is the first report about an MPase that could be produced in the culture supernatant. Furthermore, these investigations showed that this MPase is one of the most thermostable ones reported so far.

Bacillus↗
PubMed2001

High-level secretory production of phospholipase A1 by Saccharomyces cerevisiae and Aspergillus oryzae.

Phospholipase A1 (PLA1) is a hydrolytic enzyme that catalyzes the removal of the acyl group from position 1 of lecithin to form lysolecithin. The PLA1 gene, which had been cloned from Aspergillus oryzae, was expressed in Saccharomyces cerevisiae and A. oryzae. Through the modification of the medium composition and the feeding conditions of substrate, the production level of PLA1 by S. cerevisiae was increased to a level fivefold higher than that indicated in a previous report. In the case of A. oryzae, introduction of multicopies of PLA1 expression units, and the morphological change from the pellet form to the filamentous form were effective for the enhancement of PLA1 production. We succeeded in producing 3,500 U/ml of PLA1 using an industrial-scale fermentor.

Aspergillus oryzae↗
PubMed2000

Effect of ethanol on the production of carboxypeptidase Y using the GAL10 promoter in a Saccharomyces cerevisiae gal80 mutant.

In the course of studying carboxypeptidase Y (CPY) production, we found that the expression level of the gene, which is under the control of the GAL10 promoter, increased in a Saccharomyces cerevisiae gal80 mutant grown in a medium containing ethanol as the sole carbon source. In the cultivation of the gal80 mutant KS58-2D/pCY303 carrying a multicopy plasmid, which contains the PRC1 gene fused to the GAL10 promoter, CPY production continued after the consumption of galactose. In this phase, the cells utilized ethanol as the carbon source. To increase the CPY production level, we examined the effect of carbon source feeding in a fed-batch culture. The production level in the fed-batch culture using ethanol was 1.3-fold higher than that in a batch culture and 1.6-fold higher than that in a fed-batch culture using galactose. By 5'-deletion analysis of the GAL10 promoter, the region between -256 and -232 was found to be important for the promoter activity in the gal80 mutant growing in the presence of ethanol.

Journal Article↗
PubMed2000

Process development for industrial-scale preparation of carboxypeptidase Y secreted by Saccharomyces cerevisiae.

A method for industrial-scale preparation of carboxypeptidase Y (CPY), which was secreted by Saccharomyces cerevisiae KS58-2D/pCY303 into the culture broth, was developed. Because the purification process consists of a few simple unit operations including only one chromatography step, a higher CPY recovery was achieved than that in the process using disrupted baker's yeast. Approximately 100 g of purified CPY powder was constantly obtained using the final culture broth from a 500-l fermentor.

Journal Article↗
PubMed1999

Large-scale preparation of recombinant human calcitonin from a multimeric fusion protein produced in Escherichia coli.

In order to develop a large-scale, high-yield production process for human calcitonin (hCT) in Escherichia coli, a stable expression plasmid was constructed and the expressed protein was modified for efficient cleavage by protease. Multiple copies of a synthetic gene encoding hCT-Leu-Arg, a substrate for C-terminal amidation by carboxypeptidase Y (CPY), were inserted into the stable expression plasmid. Using this plasmid, the expression of a multimeric fusion protein was induced by shifting the temperature from 34 to 38 degrees C. The multimeric fusion protein was accumulated as inclusion bodies. After the fermentation, the cells were harvested and disrupted by a homogenizer. The insoluble multimeric fusion protein was suspended in 6.6 M urea solution. At this time, however, the protein could not be solubilized and thus the efficiency of cleavage by protease was low. To solubilize the protein and protect Lys residues against digestion by trypsin, the protein was citraconilated with citraconic anhydride. Following S-sulfonation with Na2SO3-CuSO4, almost all the protein was solubilized. The solubilized, citraconilated, and S-sulfonated protein was digested with trypsin efficiently. By treatment with trypsin, the multimeric fusion protein was cleaved into monomers of citraconilated and S-sulfonated hCT-Leu-Arg (S-hCT-Leu-Arg). The subsequent decitraconilation was performed at low pH. S-hCT-Leu-Arg, isolated by preparative HPLC, was directly converted into S-hCT-HN2 by CPY without removal of the Arg residue. Finally, S-hCT-NH2 was desulfonated and converted into mature hCT. In this way, a large amount of recombinant mature hCT was obtained in a tank fermentation. To our knowledge, this is the first report of industrial-scale, human calcitonin production using a multimeric fusion protein expression system.

Journal Article↗
PubMed1999

Phosphodiesterase type III inhibitor, cilostazol, inhibits colon cancer cell motility.

Metastasis of cancer cells is initiated by the cellular migration into extracellular matrix and surrounding vessels. We previously showed that elevation of cAMP levels in cancer cells suppressed trans-cellular migration in vitro. Drugs that can elevate cAMP levels in cancer cells effectively may be applied to prevent metastasis in cancer patients. Cilostazol, an oral anti-platelet drug, is a specific cAMP phosphodiesterase type III inhibitor and has been clinically used to treat thrombosis patients. In chemotaxis assay, cellular migration of human colon cancer cells, DLD- 1, was induced by 10 microg/ml of soluble fibronectin or 10% of fetal bovine serum (FBS). Treatment with cilostazol (50 microM) suppressed 92.3% or 84.6% of the migration in control cells, respectively. When DLD-1 cells were stimulated by soluble fibronectin in phagokinetic assay, migration assessed by the area of gold particle phagocytosis track was induced and cilostazol also decreased 67.3% of the cellular migration in control cells. Furthermore, in the trans-cellular migration assay, cilostazol suppressed cancer cell invasion induced by FBS. Thus, cilostazol can suppress colon cancer cell motility and might be effective as an anti-metastasis drug for cancer patients.

Animals↗
PubMed1998

Gangliosides and sialylcholesterol as modulators of synaptic functions.

Gangliosides were shown to enhance the release of acetylcholine from synaptosomes on stimulation. The influx of calcium ion into synaptosomes on membrane depolarization was increased by gangliosides. This was hypothesized to be an underlying mechanisms for the enhancement of acetylcholine release. Studies using calcium channel blockers revealed that four distinct types of voltage-dependent calcium channels occurred in cerebrocortical synapses, and that the N-type was primarily responsible for the evoked release of acetylcholine. An additional result suggests that gangliosides may act mainly on the N-type calcium channel. Cholinergic-specific gangliosides, Chol-1 alpha, were assumed to participate in the mechanism of high-affinity choline uptake. These two different actions of gangliosides were found to be mimicked by synthetic ganglioside analogs. Calcium influx was increased by alpha-sialylcholesterol, and choline uptake was accelerated by beta-sialylcholesterol. Gangliosides and sialylcholesterol having these apparently beneficial effects were shown to ameliorate decreased functions of synapses from aged brains.

Acetylcholine↗
PubMed1998

Process development for high-level secretory production of carboxypeptidase Y by Saccharomyces cerevisiae.

In order to develop a production process for carboxypeptidase Y (CPY, yeast vacuolar protease) secreted by Saccharomyces cerevisiae KS58-2D, medium composition, culture conditions, and expression systems were investigated. We found that the addition of histidine to thiamine-free medium, in which CPY production was almost negligible, raised the intracellular thiamine level, resulting in the increase of CPY production. On the basis of the choice of an expression system that uses an inducible GAL10 promoter, reassessment of histidine concentration in the medium, and optimization of the pH level during cultivation (pH 6.5), active CPY was secreted in a quantity of over 400 mg/l, which was more than tenfold that higher than that previously reported. The process developed could be easily scaled-up to industrial-scale fermentation.

Biomass↗
PubMed1997

The P-OLE1 gene of Pichia angusta encodes a delta 9-fatty acid desaturase and complements the ole1 mutation of Saccharomyces cerevisiae.

Three PCR-amplified DNA fragments hybridizing with the OLE1 gene encoding delta 9-fatty acid desaturase of Saccharomyces cerevisiae were obtained using, respectively, genomic DNAs of one strain each of Kluyveromyces thermotolerans, Pichia angusta and Yarrowia lipolytica as templates. A gene designated P-OLE1 was cloned from the above fragment of P. angusta and sequenced. An open reading frame of P-OLE1 encodes a 49.6-kDa protein consisting of 451 amino acid residues, which shows high identity (62%) and similarity (89%) to that deduced from the OLE1 nucleotide sequence. Expression of P-OLE1 driven by the S. cerevisiae GAP promoter or its own promoter complemented the ole1 mutation of S.cerevisiae. Transcription of P-OLE1 in the native host was suggested to be partially repressed by oleic acid in the medium, as was that of OLE1 in S. cerevisiae and a similar gene in Y. lipolytica, but that of a similar gene in K. thermotolerans was not.

Amino Acid Sequence↗
PubMed1996

In vivo macrophage-stimulation activity of the enzyme-degraded water-soluble polysaccharide fraction from a marine alga (Gracilaria verrucosa).

The water-soluble polysaccharide fraction from Gracilaria verrucosa (GWS) has been reported to increase the phagocytic activity of mice [Yoshizawa et al., Nippon Shokuhin Kogyo Gakkaishi, 41, 557-560 (1994)]. In this study, the macrophage-stimulation activity of enzyme-degraded GWS (GWS-E) was investigated by intraperitoneally and orally administering GWS-E to mice. The intraperitoneal administration of GWS-E increased the number of peritoneal exudate cells (PEC), and increased the phagocytic activity and oxygen radical-secreting activity (spontaneous chemiluminescence) of PEC. This administration could also stimulate splenic macrophages (SPM), increasing radical-secreting activity. When GWS-E was administered orally, the radical-secreting activity of PEC and SPM increased. In this case of oral administration, the activity of SPM increased in a dose-dependent manner, while that of PEC had an optimum dose. These results indicate that GWS-E had macrophage-stimulation activity in vivo and would be suitable as a source for a physiologically functional food with protective and immunopotentiating activity.

Administration, Oral↗
PubMed1995

Macrophage stimulation activity of the polysaccharide fraction from a marine alga (Porphyra yezoensis): structure-function relationships and improved solubility.

The polysaccharide fraction from Porphyra yezoensis (PASF) has already been shown to stimulate murine phagocytic functions in vivo and in vitro [Y. Yoshizawa et al., Biosci. Biotech. Biochem., 57, 1862-1866 (1993)]. In this study, various treatments were applied to PASF to assess its structure-function relationships. Desulfation of PASF decreased in vitro macrophage-stimulation activity, while further sulfation of PASF did not change the activity. Among 7 fractions obtained by anion-exchange chromatography of PASF, stronger activity was found in the fractions having a lower or higher sulfate content than in those having a medium sulfate content. Digests of PASF with beta-agarase showed higher activity and solubility, and lower viscosity, than undigested PASF. These results indicate that the sulfate groups in PASF, probably porphyran, contributed to the macrophage stimulating activity, although a larger number of sulfate groups did not always cause stronger activity.

Animals↗
PubMed1992

Purification and characterization of a novel dipeptidyl carboxypeptidase from a Streptomyces species.

An extracellular protease derived from the culture broth of a microorganism, a Streptomyces species, produced Boc-Pro-Pro and diproline from Boc-Pro-Pro-Pro-Pro. The enzyme was purified 726-fold, with a yield of 2.6%, by ammonium sulfate fractionation, ion-exchange chromatography, and gel filtration chromatography. The molecular weight of the enzyme was determined to be 65,000 by gel filtration and 70,000 by SDS-PAGE. The enzyme released a C-terminal dipeptide from peptide substrates having a C-terminal proline and a penultimate proline or alanine residue, but did not hydrolyze angiotensin I or bradykinin. When the enzyme hydrolyzed Leu-Pro-Pro-Pro-Pro-Pro, it produced Leu-Pro-Pro-Pro and Pro-Pro before producing Leu-Pro. The enzyme thus seems to be a kind of dipeptidyl carboxypeptidase, its substrate specificity being very different from that of the well known dipeptidyl carboxypeptidases [EC 3.4.15.1] such as the angiotensin-converting enzyme.

Amino Acid Sequence↗
PubMed1991

Effects of vitamin E-enriched egg yolk on lipid peroxidation, hemolysis and serum lipid concentration in young and old rats.

Effects of a diet containing different amount of vitamin E-enriched egg yolk powder on lipid peroxidation, hemolysis, and serum lipid concentration were examined in young and old rats. Young and old rats were fed experimental diets containing 5.6% or 22.5% of normal egg yolk powder, and 5.6% or 22.5% of vitamin E-enriched egg yolk powder. When young rats were fed these diets, their tocopherol concentrations in testes, heart, kidneys, and retroperitoneum fat pads increased according to the diet tocopherol contents. Lipid peroxide levels in these tissues were inversely proportional to the tocopherol concentrations. The liver and serum, however, did not show the above relationship. In the rats fed vitamin E-enriched egg yolk diets hemolysis did not increase, in contrast to those fed normal egg yolk diets. The rats fed a 5.6% vitamin E-enriched egg yolk diet had a lower serum cholesterol level than those fed a normal egg yolk diet. In old rats, one control group was used to determine initial tocopherol concentration and two other groups were fed 5.6% normal and vitamin E-enriched egg yolk diets. The vitamin E-enriched egg yolk rats showed lower weights of the body, liver, and retroperitoneum fat pads at the end of the experiment. The normal egg yolk group had atrophied testes. The tissue and serum tocopherol concentrations were increased in the vitamin E-enriched egg yolk group, whereas they were decreased in the normal egg yolk group. In the vitamin E-enriched egg yolk group, lipid peroxide, hemolysis and serum cholesterol, especially HDL-cholesterol, did not increase. These results indicate that egg yolk tocopherol was absorbed and prevented lipid peroxidation and hemolysis in young and old rats, and testes atrophy in old rats.

Age Factors↗
PubMed1991

Structures and activity of angiotensin-converting enzyme inhibitors in an alpha-zein hydrolysate.

Peptides that inhibit angiotensin-converting enzyme (ACE) were isolated from alpha-zein hydrolysate prepared with thermolysin. Their chemical structures were identified by Edman degradation and fast-atom bombardment mass spectrometry. Most of them were found to be tripeptides such as Leu-Arg-Pro, Leu-Ser-Pro, and Leu-Gln-Pro, having IC50 values of 0.27, 1.7, and 1.9 microM, respectively. These peptides were synthesized by a solid phase procedure and had similar ACE inhibitory activities as the isolated inhibitors. The hypotensive activity of Leu-Arg-Pro on spontaneously hypertensive rats was also investigated, with the result that the the blood pressure decreased by 15 mmHg after a 30 mg/kg intravenous injection.

Amino Acid Sequence↗
PubMed1984

The fine structures of the VIP-like immunoreactive neurons in the cat hypothalamus.

The fine structures of the VIP-like immunoreactive neurons in the suprachiasmatic nucleus (SCN) and the arcuate nucleus ( ARN ) of the cat hypothalamus were investigated by electron microscopic immunocytochemistry. The VIP-like immunoreactive soma and fibers could be successfully visualized by a modified PAP method. VIP-like immunoreactive neurons in both nuclei contained immunoreactive rER, Golgi complexes and many immunoreactive granules, as well as well developed mitochondria. VIP-like immunoreactive synaptic endings with synaptic membrane specialization of Gray's type I and II were found in the SCN. Moreover VIP-like immunoreactive preterminal elements that made synaptic contact with VIP-like immunoreactive neuronal soma were also detected. On the other hand, it was difficult to detect typical preterminal endings with immunoreactivity in the ARN ; however, VIP-like immunoreactive processes in contact with the basement membrane of the capillaries were observed. These observations indicate that VIP-like immunoreactive neurons in the SCN act as intrinsic neurons and are involved in neuroendocrine function in ARN .

Animals↗