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21.
Yazaki Yoshiaki; Maki Kazutoshi; Sato Tetsuya; Ohta Eiji; Sakata Makoto 《Plant & cell physiology》1988,29(8):1417-1422
The intracellular K+ concentration and its change in mung bean[Vigna mungo (L.) Hepper] root tips were investigated non-invasivelywith 39K nuclear magnetic resonance spectroscopy using a membraneimpermeable shift reagent, dysprosium (III) tripolyphosphate[Dy(PPPi)72]. The K+ resonance was shifted to highermagnetic field in proportion to the concentration of the shiftreagent. In addition to a reference capillary peak for measuringthe K+ concentration, two well-resolved peaks (intra- and extracellularK+ resonances) were observed in the 39K NMR spectra of mungbean root tips. The intracellular K+ concentration was determinedto be 41 mM, which was similar to the value obtained by flamephotometry. When 20 mM KCl was added to the external medium,the intensity of the intracellular K+ resonance gradually increasedand the net K+ uptake rate was calculated to be 4.1 micromolesper gram fresh weight per hour. After removal of KCl from theperfusion medium, the intracellular K+ concentration considerablydecreased. With 31P NMR method, 2.5 mM Dy(PPPj)712 and20 mM KCl had little effect on the ATP level in the cells. Wehave indicated that the 39K NMR method can be used to determinethe K+ levels and net fluxes of the K+ transport in perfusedroot tips successively. (Received April 6, 1988; Accepted September 29, 1988) 相似文献
22.
Tomohiko Suzuki Akio Nakamura Yoshiaki Satoh Chisato Inai Takahiro Furukohri Tomikazu Arita 《Journal of Protein Chemistry》1992,11(6):629-633
The blood clamBarbatia virescens has a heterodimeric hemoglobin in erythrocytes. Interestingly, the congeneric clamsB. reeveana andB. lima contain quite different hemoglobins: tetramer and polymeric hemoglobin consisting of unusual didomain chain. The complete amino acid sequence of chain I ofB. virescens has been determined. The sequence was mainly determined from CNBr peptides and their subpeptides, and the alignment of the peptides was confirmed by sequencing of PCR-amplified cDNA forB. virescens chain I. The cDNA-derived amino acid sequence matched completely with the sequence proposed from protein sequencing.B. virescens chain I is composed of 156 amino acid residues, and the molecular mass was calculated to be 18,387 D, including a heme group. The sequence ofB. virescens chain I showed 35–42% sequence identity with those of the related clamAnadara trapezia and the congeneric clamB. reeveana. An evolutionary tree forAnadara andBarbatia chains clearly indicates that all of the chains are evolved from one ancestral globin gene, and that the divergence of chains has occurred in each clam after the speciation. The evolutionary rate for clam hemoglobins was estimated to be about four times faster than that of vertebrate hemoglobin. We suggest that blood clam hemoglobin is a physiologically less important molecule when compared with vertebrate hemoglobins, and so it evolved rapidly and resulted in a remarkable diversity in quaternary and subunit structure within a relatively short period. 相似文献
23.
Yoshiaki Sumiyoshi Masahiko Kikuchi Morishige Takeshita Kohiti Ohshima Yuhiti Masuda 《Virchows Archiv. B, Cell pathology including molecular pathology》1992,61(1):201-207
In Japan, histiocytic necrotizing lymphadenitis (Kikuchi’s disease) is a relatively common reactive lesion affecting lymph
nodes, but the histogenesis and pathogenesis of the disease have not been clarified. Alpha-interferon has a role in the body’s
defense against, viral infections. Using a polyclonal antibody to human alpha-interferon, we found numerous cells, mainly
histiocytes, containing alpha-interferon in affected foci in the lymph nodes from 24 patients with Kikuchi’s disease. Tubuloreticular
structures, thought by some authors to be associated with the production of interferon, were detected by electron microscopy
in histiocytes, activated lymphocytes and vascular endothelial cells in the affected foci. These results suggested that the
formation of tubuloreticular structures is a secondary phenomenon following stimulation by alpha-interferon. Further, the
activity of 2′–5′ oligoadenylate synthetase, which is induced by alpha-interferon and enhanced during the early or active
stage of viral infection, showed increased levels of activity in the active stage of Kikuchi’s disease and decreased to normal
levels in the convalescent stage 2 weeks later. These results suggested the possibility of a viral etiology for Kikuchi’s
disease. 相似文献
24.
Complete nucleotide sequence of the mitochondrial DNA from a liverwort,Marchantia polymorpha 总被引:1,自引:1,他引:0
Kenji Oda Katsuyuki Yamato Eiji Ohta Yasukazu Nakamura Miho Takemura Naoko Nozato Kinya Akashi Takeshi Kanegae Yutaka Ogura Takayuki Kohchi Kanji Ohyama 《Plant Molecular Biology Reporter》1992,10(2):105-163
Libraries of cosmid and plasmid clones covering the entire region of mtDNA from the liverwortMarchantia polymorpha were constructed. These clones were used for the determination of the complete nucleotide sequence of the liverwort mtDNA
totally 186,608 bp (GenBank no. M68929) and including genes for 3 species of ribosomal RNAs, 29 genes for 27 species of transfer
RNAs, and 30 genes for functionally known proteins (16 ribosomal proteins, 3 subunits of cytochromec oxidase, apocytochromeb protein, 3 subunits of H+-ATPase, and 7 subunits of NADH ubiquinone oxidoreductase). The genome also contains 32 unidentified open reading frames.
Thus the complete nucleotide sequences from both chloroplast and mitochondrial genomes have been determined in the same organism.
Plasmid clones are available upon the request.
Gene names are represented according to Lonsdale and Leaver (1988) with modifications recommended by Lonsdale (personal communication). 相似文献
25.
Fujita Yuichi; Takahashi Yasuhiro; Shonai Fumio; Ogura Yutaka; Matsubara Hiroshi 《Plant & cell physiology》1991,32(7):1093-1106
The frxC gene, found in liverwort chloroplast DNA, encodes aprotein of unknown function. The deduced amino acid sequenceof the protein shows significant homology to that of ni-trogenaseFe-protein encoded by the nifH gene. We have cloned the frxCand nifH genes from the nitrogen-fixing cyanobacterium Plectonemaboryanum, using frxC- and nifH-specific probes, and have determinedtheir nucleotide sequences. The amino acid sequence deducedfrom the frxC gene of P. boryanum exhibits 83% homology to thatof the protein encoded by the/rxCgene from liverwort, whereasit exhibits only 34% homology to that encoded by the nifH genefrom the same organism, namely, P. boryanum. Northern blot analysisshowed that the frxC gene was transcribed more actively undernitrogenase-repressed conditions than under nitrogenase-inducedconditions, suggesting that the FrxC protein has a functiondistinct from nitrogen fixation. These results, together withthe phylogenetic relationship between the nifH and frxC genes,indicate that the frxC and nifH genes are derived from a commonancestral gene but have evolved independently to encode proteinswith different functions. (Received April 27, 1991; Accepted August 12, 1991) 相似文献
26.
Shinjiro Mitsuda Naoki Kobayashi Yoshiaki Matsuda Yasuharu Itagaki Akira Suzuki Eitaro Kumazawa Kanji Higashio Gosei Kawanishi 《Applied microbiology and biotechnology》1991,35(4):504-509
Summary Tissue plasminogen activator (t-PA) production induced by proteose peptone from IMR-90 cells was investigated. Cells monolayered on plastic surfaces had a higher ability to produce t-PA per unit cell compared to those grown tri-dimensionally on ceramic pieces. Furthermore, confluent monolayers of the cells, which suffered contact inhibition and resulted in limited growth, were available for t-PA production. Repeated batch production with microcarriers, on which the cells were almost confluent monolayers similar to those in T-flasks, was performed. Utilization of the cells, which had limited serum in the growth phase, resulted in an increase in production. Moreover, dilution of the basal components of the medium at initiation of the production phase markedly promoted t-PA production. The volumetric productivity was stable for 30 days at 100 IU/cm3 per day. The cells were then mostly retained on microcarriers. Thus, an effective and scalable method of t-PA production by normal fibroblast cells was developed.
Offprint requests to: S. Mitsuda 相似文献
27.
Interleukin-4 downregulates interleukin-6 production by human alveolar macrophages at protein and mRNA levels. 总被引:2,自引:0,他引:2
Effects of interleukin-4 (IL-4) on IL-6 production by human alveolar macrophages (AM) obtained by bronchoalveolar lavage from healthy donors was examined at the protein and gene levels. IL-6 production was quantitated by enzyme immunoassay (EIA) and bioassay using the IL-6 dependent murine hybridoma cell line MH60.BSF2. Results showed that when activated with LPS, AM released significantly more biologically active IL-6 than blood monocytes. Human rIL-4 significantly suppressed IL-6 production by AM and monocytes stimulated with LPS. Northern blot analysis revealed that IL-4 reduced the expression of IL-6 mRNA in LPS-stimulated AM and monocytes. The inhibitory effect was most pronounced when IL-4 was added with LPS or within the first 4 hr after LPS to AM or monocytes. The suppressive effect of IL-4 was completely neutralized by pretreatment with anti-IL-4 antibody. IL-4 also showed a suppressive effect on IL-6 production by macrophages generated in vitro by maturation of blood monocytes with granulocyte-macrophage colony stimulating factor (GM-CSF). These observations suggest that IL-4 may play a critical role in in situ regulation of immune responses through suppression of IL-6 production. 相似文献
28.
Preliminary comparisons are presented, of certain diagnostic characters of four species of Canthocamptus, all the specimens examined here being collected from freshwater bodies throughout Japan. The geographical distribution of each species is also discussed.Contribution No. 69 from the Itako Hydrobiological Station, Ibaraki University. 相似文献
29.
Chromosomal genes essential for stable maintenance of the mini-F plasmid in Escherichia coli 总被引:6,自引:6,他引:0
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H Niki C Ichinose T Ogura H Mori M Morita M Hasegawa N Kusukawa S Hiraga 《Journal of bacteriology》1988,170(11):5272-5278
We have isolated mutants of Escherichia coli which do not support stable maintenance of mini-F plasmids (delta ccd rep+ sop+). These host mutations, named hop, were classified into five linkage groups on the E. coli chromosome. Genetic analyses of these hop mutations by Hfr mating and P1 transduction showed their loci on the E. coli genetic map to be as follows: hopA in the gyrB-tnaA region, hopB in the bglB-oriC region, hopD between 8 and 15 min, and hopE in the argA-thyA region. Kinetics of stability of the sop+ and delta sop mini-F plasmids in these hop mutants suggest that the hopA mutants are defective in partitioning of mini-F rather than in plasmid replication. The hopB, hopC, and hopD mutants were partially defective in replication of mini-F. The physical structure of the plasmid DNA was normal in hopA, B, C, and D mutants. Large amounts of linear multimers of plasmid DNA accumulated in mutants of the fifth linkage group (hopE). None of the hop mutations in any linkage group affected the normal growth of cells. 相似文献
30.
T Watabe A Hiratsuka K Ogura 《Biochemical and biophysical research communications》1986,134(1):100-105
Potent mutagenicity of 7,12-dihydroxymethylbenz[a]anthracene (DHBA) toward Salmonella typhimurium TA 98 in the presence of rat liver cytosol fortified with 3'-phosphoadenosine 5'-phosphosulfate (PAPS) was completely retarded by the addition of glutathione (GSH). The reactive and intrinsically mutagenic metabolite, DHBA 7-sulfate, formed by hepatic cytosolic sulfotransferase disappeared from the incubation mixture by the addition of GSH. Non-mutagenic S-(12-hydroxymethylbenz[a]anthracen-7-yl)methylglutathione was isolated from the incubation mixture consisting of the hepatic cytosol, DHBA, PAPS, and GSH and proved to be formed by GSH S-transferase directly from DHBA 7-sulfate as an obligatory intermediate. 相似文献