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161.
Claire Zehnacker Thomas W. Becker Akira Suzuki Elisa Carrayol Michel Caboche Bertrand Hirel 《Planta》1992,187(2):266-274
Ferredoxin-dependent glutamate synthase (Fd-GOGAT, EC 1.4.7.1) was purified to electrophoretic homogeneity from leaves of tobacco (Nicotiana tabacum L.). The holoenzyme is a monomeric flavoprotein with a molecular weight of 164 kDa. Polyclonal rabbit antibodies against the purified enzyme were used to isolate a 450-bp Fd-GOGAT cDNA clone (C16) from a tobacco gt11 expression library. A longer Fd-GOGAT cDNA clone (C35) encoding about 70% of the amino acids of tobacco Fd-GOGAT was isolated from a tobacco gt10 cDNA library using C16 as the probe. The amino-acid sequence of the protein encoded by the Fd-GOGAT cDNA clone C35 was delineated. It is very likely that Fd-GOGAT is encoded by two genes in the amphidiploid genome of tobacco while only a single Fd-GOGAT gene appears to be present in the diploid genome of Nicotiana sylvestris. Two Fd-GOGAT isoenzymes could be distinguished in extracts of tobacco leaf protein. In contrast, a single Fd-GOGAT protein species was detected in leaves of Nicotiana sylvestris speg. et Comes. In tobacco leaves, the 6-kb Fd-GOGAT mRNA is about 50-fold less abundant than chloroplastic glutamine synthetase (EC 6.3.1.2) mRNA. Both Fd-GOGAT mRNA and Fd-GOGAT protein accumulated during greening of etiolated tobacco leaves, and a concomitant increase in Fd-GOGAT activity was observed. These results indicate that tobacco Fd-GOGAT gene expression is light-inducible. Levels of Fd-GOGAT mRNA in tobacco organs other than leaves were below the detection limit of our Northern-blot analysis. Polypeptides of Fd-GOGAT were present in tobacco leaves and, to a lesser extent, in pistils and anthers, but not in corollas, stems and roots. These results support organ specificity in tobacco Fd-GOGAT gene expression.Abbreviations bp
base pairs
- Fd-GOGAT
ferredoxin-dependent glutamate synthase
- GS
glutamine synthetase
- PAGE
polyacrylamide gel electrophoresis
- SDS
sodium dodecyl sulfate
The authors wish to thank Juan Luis Gómez Pinchetti (Marine Plant Biotechnology Laboratory) for his assistance during the experiments. This study was supported by grants received from SAREC (Swedish Agency for Research Cooperation with Developing Countries), Carl Tryggers Fund for Scientific Research (K. Haglund), SJFR (Swedish Council for Forestry and Agricultural Research) (M. Björk, M. Pedersén), CITYT Spain (SAB 89-0091 and MAR 91-1237, M. Pedersén) and CICYT Spain (Z. Ramazanov, invited professor of Ministerio de Educatión y Ciencia, Spain). The planning of this cooperation was facilitated by COST-48. 相似文献
162.
Proteins and Carbohydrates in Xylem Sap from Squash Root 总被引:8,自引:0,他引:8
Satoh Shinobu; Iizuka Chika; Kikuchi Akira; Nakamura Norio; Fujii Tadashi 《Plant & cell physiology》1992,33(7):841-847
The xylem sap from squash roots was collected from the cut surfaceof stems, and the proteins and carbohydrates in the sap wereanalyzed. The sap contained 18.6 µg ml1 proteinand the major polypeptides were as follows: 1) two polypeptides,of 75 and 40 kDa, with high-mannose glycans, the levels of whichincreased for about 24 h after cutting and then decreased; 2)a 32-kDa polypeptide, which appeared soon after cutting, disappearedand then reappeared again 4864 h after cutting; and 3)a 19-kDa and a 14-kDa polypeptide, which were present constitutively.The carbohydrates contained in the xylem sap were fractionatedinto 80% ethanol-soluble and -insoluble material, and whichwere analyzed by high-performance liquid chromatography, gaschromatography and enzymatic mathods. The former fraction containedconsiderable amounts of myo-inositol and fructose as free sugarsand oligosaccharides composed mainly of galactose, arabinoseand glucose. The latter contained polysaccharides composed mainlyof uronic acids, galactose and arabinose. The possible significanceof these substances, which may mediate the interactions betweenthe root and the aerial organs, is discussed. (Received April 20, 1992; Accepted July 4, 1992) 相似文献
163.
Kuriyama Akira; Takeuchi Masayuki; Kawai Fumio; Kanamori Masao 《Plant & cell physiology》1992,33(5):647-650
The formation of sporophytic shoots, which is induced by treatmentwith benzylaminopurine of gametophyte tissue of Equisetum arvense,can be divided into initiation and developmental phases. Thenitrogen in MS medium was suitable for two phases as well as gametophytic growth, buta reduction in the concentration of available nitrogen was neededfor the development of shoots. ions alone were effective for gametophytic growth and the initiationof sporophytic shoots, but both and ions was required for the developmental phase. (Received February 18, 1992; Accepted April 14, 1992) 相似文献
164.
Adenine depurination and inactivation of plant ribosomes by an antiviral protein of Mirabilis jalapa (MAP) 总被引:4,自引:0,他引:4
Jiro Kataoka Noriyuki Habuka Masashi Miyano Chikara Masuta Akira Koiwai 《Plant molecular biology》1992,20(6):1111-1119
Mirabilis antiviral protein (MAP) is a single-chain ribosome-inactivating protein (RIP) isolated from Mirabilis jalapa L. It depurinates the 28S-like rRNAs of prokaryotes and eukaryotes. A specific modification in the 25S rRNA of M. jalapa was found to occur during isolation of ribosomes by polyacrylamide/agarose composite gel electrophoresis. Primer extension analysis revealed the modification site to be at the adenine residue corresponding to A4324 in rat 28S rRNA. The amount of endogenous MAP seemed to be sufficient to inactivate most of the homologous ribosomes. The adenine of wheat ribosomes was also found to be removed to some extent by an endogenous RIP (tritin). However, the amount of endogenous tritin seemed to be insufficient for quantitative depurination of the homologous ribosomes.Endogenous MAP could shut down the protein synthesis of its own cells when it spreads into the cytoplasm through breaks of the cells. Therefore, we speculate that MAP is a defensive agent to induce viral resistance through the suicide of its own cells. 相似文献
165.
Yoshiharu Inoue Hiromi Tsuchiyama Nobuhiko Kosugi Akira Kimura 《Applied microbiology and biotechnology》1992,36(4):469-472
Summary Glyoxalase I was extracted from Hansenula mrakii IFO 0895 by incubating the cells with buffer solution containing 50% acetone (enzyme activity 35 units/g cells) or 50% ethyl acetate (enzyme activity 28 units/g cells) at 30°C for 10 h. Glyoxalase II was also extracted from the cells, although the activity of the enzyme was lost during incubation with organic solvents, especially at higher temperature (30°C). By using the organic-solvent-extracted fraction of H. mrakii, enzymatic production of S-lactoylglutathione was studied, and approximately 82 mmol/l (30 g/l) of S-lactoylglutathione was produced from 120 mmol/l glutathione.
Offprint requests to: A. Kimura 相似文献
166.
Haruo Nagayama Koji Nagano Akira Ikezaki Tetsuo Tashiro 《Chronobiology international》1991,8(3):203-209
To investigate the possibility of chronotherapy with antidepressants for patients with depression, we gave single daily doses of clomipramine 150 mg/day to 30 patients with depression at three different times of day, i.e., morning, noon, or before bedtime, using a double-blind method over a 4-week period. Beneficial effects differed according to the administration time of day, with the most effective result being found for the administration at noon. Time-dependent differences in side effects were observed in tremors and dryness of mouth. An additional 10 patients were administered their medications three times a day by traditional, equally divided doses, and the efficacy was inferior than daily single doses at noon. The study results showed the significance of the administration time of day for the benefits and side effects of antidepressant therapy for depression. 相似文献
167.
Summary The kinetic process of folding of bovine pancreatic ribonuclease A in a2H2O environment at pH 1.2 was examined by a recently developed temperature-jump NMR method (Akasaka et al., (1990) Rev. Sci. Instrum.61, 66–68). Upon temperature-jump down from 45°C to 29°C, which was attained within 6 s, the proton NMR spectral changes were followed consecutively in time intervals of seconds. There was a rapid spectral change, which was finished within the jump period, followed by a much slower process which lasted for a minute or longer. Rates of the slower process were measured at different positions of the polypeptide chain as intensity changes of individual His and Tyr proton signals of the folded conformer and as intensity changes of aliphatic and His protons of the unfolded conformer. Most of these rates coincided with each other within experimental error with an average value of 2.8×10–2s–1. The result gave clear experimental evidence that the slow folding of RNase A at low pH is a cooperative process involving most regions of the molecule, not only thermodynamically, but kinetically as well. 相似文献
168.
The behavior of chum slamon,Oncorhynchus keta, was studied using ultrasonic telemetry in the waters off the Okhotsk coast of Hokkaido from 1979 to 1981. Thirty-six adult
fish were outfitted with a 50 KHz ultrasonic transmitter provided with either a depth sensor, depth/illumination sensors,
or depth/ temperature sensors. Twenty-one of the experimental fish were used as controls and left intact. Of the remaining
fish, six had their sight destroyed, seven had their olfactory nerves severed or their nares filled with wax, one had both
senses destroyed, and one had a sham operation, but had only a shallow transverse cut made in the skin over the olfactory
nerves. Control fish and the fish with the sham operation initially swam in a horizontal zigzag pattern while fish with an
obliterated sense swam in a similar pattern but to a reduced extent. The horizontal and vertical speeds of the intact fish
were faster than those of the fish with a destroyed sense. Amplitude of vertical movements of the intact fish stretched from
surface to bottom, while fish with destroyed vision tended towards midwater. Fish without an olfactory sense tended to be
at the surface or near the bottom. Regular vertical movement would be effective in refreshing olfactory epithelia which might
become acclimated when exposed to one odor. The vertical movements can be found in the horizontal zigzag movements in coastal
and near shore migrations, as well as in the stream phase of homing. The zigzag movements, both horizontal and vertical, allow
the fish to sense the water masses and locate the correct tributary. 相似文献
169.
Kazunori Maruyama Kouji Nagata Minoru Tanaka Hiromichi Nagasawa Akira Isogai Hironori Ishizaki Akinori Suzuki 《The protein journal》1992,11(1):1-12
We report the synthesis of bombyxin-IV, a disulfide-linked, heterodimeric, insulin superfamily peptide from the silkworm,Bombyx mori. The two chains (A- and B-chains) were synthesized separately by the solid-phase method using fluoren-9-ylmethoxycarbonyl (Fmoc) group as a protecting group for α-amino group. Three disulfide bonds were bridged step by step (A6–A11, A20–B22, and A7–B10) in a good yield. Synthetic bombyxin-IV was identical with natural one with regard to the retention time on a reversed-phase column and the molecular weight measured by mass spectrometry. Circular dichroism (CD) spectrum of the synthetic bombyxin-IV was very similar to that of the natural one. The specific activity of synthetic bombyxin-IV is equal to that of natural one (0.1 ng/Samia unit). These results suggest that the synthetic bombyxin-IV has the tertiary structure identical with the natural peptide. Our method developed for synthesis of bombyxin-IV would be generally applicable to the synthesis of insulin-like heterodimeric peptides. 相似文献
170.
Developmental Changes in the Bombyxin-and Insulin-like Immunoreactive Neurosecretory System in the Wax Moth, Galleria mellonella 总被引:1,自引:1,他引:0
Dun itn Frantiek Sehnal Akira Mizoguchi Hironori Ishizaki Hiromichi Nagasawa Akinori Suzuki 《Development, growth & differentiation》1990,32(6):637-645
Four medial neurosecretory cells (MNC) and 4 lateral neurosecretory cells (LNC) in each brain hemisphere, and one pair of cells in each thoracic ganglion (TG) of Galleria larva react with antibodies against bombyxin and insulin. Material secreted from the MNC and LNC is released mainly in the corpora allata, and that from the TG through the ventral median nerves. Intrinsic secretory cells of the corpora cardiaca (CC) also contain bombyxin-like, but not insulin-like material. The immunoreactivities all disappear during molts and reappear with resumption of feeding. In the MNC and TG they reappear for less than a day, but in cells of the CC immunoreactivity reappears for the whole feeding period. Before pupation, the LNC become temporarily immunopositive towards the end of feeding period, and the MNC and TG during the wandering period, i.e. at the time of prothoracic gland stimulation. Immunoreactivity disappears during the pupal molt. In pupae it is present in the 4 pairs of MNC and 1–2 pairs of LNC 12–48 hr after ecdysis, and in cells of the CC from 12 hr after ecdysis until the end of the pupal instar. In adult, immunoreactivity is restricted to 2 pairs of the LNC and to CC cells. 相似文献