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1.
The catalase molecule in germinating pumpkin cotyledons is synthesizedas a precursor (59-kDa) form, whose relative molecular massis larger than the mature enzyme (55-kDa). Although both typesof molecules are localized in the microbodies, the 59-kDa specieshas been shown to be present predominantly in the leaf peroxisomesisolated from green cotyledons, while the 55-kDa species ispredominantly in the glyoxysomes from etiolated cotyledons [Yamaguchiet al. (1984) Proc. Natl. Acad. Sci. USA, 81: 4809]. We examinedthe distribution of the 59- and 55-kDa catalase molecules indark- and light-grown tissues of pumpkin seedlings as well asin other plant species, using the immunoblotting technique.The ratios of the 59- and 55-kDa catalase species differed inthe pumpkin tissues examined. Light interferes with the conversionof the 59-kDa precursor to the 55-kDa form, especially in thecotyledons. The effect of light was less pronounced in the rootsand hypocotyls, indicating that the light regulation of theconversion is tissue-specific. Dark- and light-grown cotyledonsfrom cucumber and watermelon seedlings showed a similar lightregulation, suggesting that cucurbitaceous plants possess similarlight-regulatory mechanism. From the analysis of catalase proteinfrom various plant tissues, a limited correlation between molecularforms of catalase and different microbody populations was observed. (Received September 6, 1986; Accepted December 4, 1986) 相似文献
2.
Tadashi Noto Hiromichi Hashimoto Junji Nakao Hiroshi Kamimura Teruo Nakajima 《Journal of neurochemistry》1986,46(6):1877-1880
The spontaneous release of [3H] gamma-aminobutyric acid ([3H]GABA) in various areas of rat brain injected with [3H]putrescine was examined using a push-pull perfusion technique. The release in a 25-min perfusate was highest in the caudate-putamen. The effect of high K+ stimulation on the release of [3H]GABA formed from [3H]putrescine was examined in the caudate-putamen. The release was enhanced by high K+ solution in a Ca2+-dependent manner. 相似文献
3.
4.
Kazuhito Ohishi Yasuyuki Kurimoto Norimitsu Inoue Yuichi Endo Junji Takeda Taroh Kinoshita 《Genomics》1996,34(3):340
Many eukaryotic proteins are bound to the plasma membrane via a glycosylphosphatidylinositol (GPI) anchor. Its core backbone, which is conserved in different organisms, is synthesized in the endoplasmic reticulum by the sequential addition of glycan components to phosphatidylinositol. One of the human GPI synthesis genes,PIGF(phosphatidylinositol glycan complementation class F), which is involved late in the synthesis pathway, has been cloned. In this study, we isolated complementary and genomic clones ofPigf,a murine counterpart ofPIGF. Pigfencodes a 219 amino acid protein that complements a class F mutation. ThePigfgene consists of six exons spanning 30 kb and was mapped to chromosome 17 at 17E4–E5. These features are very similar toPIGF,thus demonstrating the interspecies conservation of structure, function, gene organization, and genetic locus between these GPI synthesis genes. The results also extend a region in murine distal chromosome 17 that is syntenic to human chromosome 2p16–p22. 相似文献
5.
Takayoshi Yoshida Hiroshi Watari 《European journal of applied physiology and occupational physiology》1994,69(6):465-473
To investigate the splitting of the inorganic phosphate (Pi) peak during exercise and recovery, a time-resolved 31phosphorus nuclear magnetic resonance spectroscopy (31P-MRS) technique was used. Seven healthy young sedentary male subjects performed knee flexion exercise in the prone position inside a 2.1-T magnet, with the surface coil for 31P-MRS being placed on the biceps femoris muscle. After a 1-min warm-up without loading, the exercise intensity was increased by 0.41 W at 15-s intervals until exhaustion, followed by a 5-min recovery period. The 31P-MRS were recorded every 5 s during the rest-exercise-recovery sequence. Computer-aided contour analysis and pixel imaging of the Pi and phosphocreatine peaks were performed. Five of the seven subjects showed two distinct Pi peaks during exercise, suggesting two different pH distributions in exercising muscle (high pH and low pH region). In these five subjects, the high-pH increased rapidly just after the onset of exercise, while the low-pH peak increased gradually approximately 60 s after the onset of exercise. During recovery, the disappearance of the high-pH peak was more rapid than that of the low-pH peak. These findings suggest that our method 31P-MRS provides a simple approach for studying the kinetics of the Pi peak and intramuscular pH during exercise and recovery. 相似文献
6.
Junji Inokoshi Hiroshi Tomoda Hideaki Hashimoto Akemi Watanabe Hideo Takeshima Satoshi ōmura 《Molecular & general genetics : MGG》1994,244(1):90-96
Cerulenin, an antifungal antibiotic produced by Cephalosporium caerulens, is a potent inhibitor of fatty acid synthase in various organisms, including Saccharomyces cerevisiae. The antibiotic inhibits the enzyme by binding covalently to the active center cysteine of the condensing enzyme domain. We isolated 12 cerulenin-resistant mutants of S. cerevisiae following treatment with ethyl methanesulfonate. The mechanism of cerulenin resistance in one of the mutants, KNCR-1, was studied. Growth of the mutant was over 20 times more resistant to cerulenin than that of the wild-type strain. Tetrad analysis suggested that all mutants mapped at the same locus, FAS2, the gene encoding the subunit of the fatty acid synthase. The isolated fatty acid synthase, purified from the mutant KNCR-1, was highly resistant to cerulenin. The cerulenin concentration causing 50% inhibition (IC50) of the enzyme activity was measured to be 400 M, whereas the IC50 value was 15 M for the enzyme isolated from the wild-type strain, indicating a 30-fold increase in resistance to cerulenin. The FAS2 gene was cloned from the mutant. Sequence replacement experiments suggested that an 0.8 kb EcoRV-HindIII fragment closely correlated with cerulenin resistance. Sequence analysis of this region revealed that the GGT codon encoding Gly-1257 of the FAS2 gene was altered to AGT in the mutant, resulting in the codon for Ser. Furthermore, a recombinant FAS2 gene, in which the 0.8 Kb EcoRV-HindIII fragment of the wild-type FAS2 gene was replaced with the same region from the mutant, when introduced into FAS2-defective S. cerevisiae complemented the FAS2 pheno-type and showed cerulenin resistance. These data indicate that one amino acid substitution (Gly Ser) in the subunit of fatty acid synthase is responsible for the cerulenin resistance of the mutant KNCR-1. 相似文献
7.
A system for induction of synthesis of 相似文献
8.
Takayoshi Yoshida Hiroshi Watari 《European journal of applied physiology and occupational physiology》1993,66(6):494-499
This study evaluated the time courses of intracellular pH and the metabolism of phosphocreatine (PCr) and inorganic phosphate (P) at the onset of four exercise intensities and recoveries. Non-invasive evaluation of continuous changes in phosphorus metabolites has become possible using31P-nuclear magnetic resonance spectroscopy (31P-MRS). After measurements at rest, six healthy male subjects performed 4 min of femoral flexion exercise at intensities of 0 (loadless), 10, 20 and 30 kg · m · min–1 in a 2.1 T superconducting magnet with a 67-cm bore. Measurements were continuously made during 5 min of recovery. During a series of rest-exercise-recovery procedures,31P-MRS were accumulated using 32 scans · spectrum–1 requiring 12.8 s each. At the onset of exercise, PCr decreased exponentially with a time constant of 27–32 s regardless of the exercise intensity. The time constant PCr resynthesis during recovery was about 27–40 s. The PCr kinetics were independent of exercise intensity. There were similar Pi kinetics at the onset of all types of exercise, while those of Pi recovery became significantly longer at the higher exercise intensities (P < 0.05). Furthermore, the intracellular pH indicated temporary alkalosis just at the onset of exercise, probably due to absorption of hydrogen ions by PCr hydrolysis, and then decrease at a point about 40%–50% of the preexercise PCr. The pH recovery time was longer than that for the Pi or PCr kinetics. By using a more efficient resolution system it was possible to obtain the phosphorus kinetics during exercise and to follow PCr resynthesis within the first few minutes of recovery. From our results it was concluded that in general the time course of PCr and Pi metabolism were unaffected by the exercise intensity, both at the onset of exercise and during recovery, with the exception of Pi recovery. 相似文献
9.
Takayoshi Yoshida Hiroshi Watari 《European journal of applied physiology and occupational physiology》1993,67(3):274-278
The rates of change in intracellular pH during repeated exercise sessions with rest periods was determined by 31 phosphorus-nuclear magnetic resonance spectroscopy (31P-MRS). Five long-distance runners and six healthy male subjects as controls performed a 2-min femoral flexion at 20 kg · m · min–1 in a 2.1 T superconducting magnet with a 67-cm bore and repeated this exercise four times with 2-min rest periods intervening. In all cases during exercise the inorganic phosphate (Pi) peak split into two, the earlier increased rapidly (high-pH Pi) and the later (low-pH Pi) increased more slowly. The Pi peaks were separated by a fitting procedure using the least square mean method. The high-pH Pi area during exercise decreased as the number of repeated exercise periods increased, while the low-pH Pi area gradually increased. Although the total Pi area decreased exponentially during the recovery period, the high-pH Pi area decreased first and then the low-pH Pi area reduced gradually. The pH values were estimated from the chemical shift between the phosphocreatine peak and each split peak in the Pi. The high-pH in pooled data ranged from 6.6 to 7.0 during exercise and recovery, while the low pH decreased to 6.2 during exercise. As the number of exercise periods increased, each pH value gradually became less acidic, although there was a tendency to more acidity in the control subjects than in the long-distance runners. In conclusion, it was possible to obtain by non-invasive, continuous31P-MRS, a split pattern of Pi peaks during exercise and there were at least tow different intracellular pH values during exercise, suggesting that each Pi peak might be attributed to the types of muscle fibre recruited. 相似文献
10.