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641.
642.
Atsushi Ishihara Rie Kumeda Noriko Hayashi Yukari Yagi Nanase Sakaguchi Yu Kokubo 《Bioscience, biotechnology, and biochemistry》2017,81(6):1090-1098
The inducible metabolites were analyzed in barley leaves inoculated with Bipolaris sorokiniana, the causal agent of spot blotch of barley. HPLC analysis revealed that B. sorokiniana-infected leaves accumulated 4 hydrophilic compounds. They were purified by ODS column chromatography and preparative HPLC. Spectroscopic analyses revealed that they were tyramine (1), 3-(2-aminoethyl)-3-hydroxyindolin-2-one (2), serotonin (3), and 5,5′-dihydroxy-2,4′-bitryptamine (4). Among these, 2 and 4 have not been reported as natural products. They showed antifungal activity in an assay of inhibition of B. sorokiniana conidia germination, suggesting that they play a role in the chemical defense of barley as phytoalexins. The accumulation of 1–4 was examined also in the leaves of rice and foxtail millet. Rice leaves accumulated 2, 3, and 4, whereas foxtail millet leaves accumulated 3 and 4 in response to pathogen attack, suggesting the generality of accumulation of 3 and 4 in the Poaceae species. 相似文献
643.
Highly reproducible tissue development is achieved by robust, time-dependent coordination of cell proliferation and cell death. To study the mechanisms underlying robust tissue growth, we analyzed the developmental process of wing imaginal discs in Drosophila Minute mutants, a series of heterozygous mutants for a ribosomal protein gene. Minute animals show significant developmental delay during the larval period but develop into essentially normal flies, suggesting there exists a mechanism ensuring robust tissue growth during abnormally prolonged developmental time. Surprisingly, we found that both cell death and compensatory cell proliferation were dramatically increased in developing wing pouches of Minute animals. Blocking the cell-turnover by inhibiting cell death resulted in morphological defects, indicating the essential role of cell-turnover in Minute wing morphogenesis. Our analyses showed that Minute wing discs elevate Wg expression and JNK-mediated Dilp8 expression that causes developmental delay, both of which are necessary for the induction of cell-turnover. Furthermore, forced increase in Wg expression together with developmental delay caused by ecdysone depletion induced cell-turnover in the wing pouches of non-Minute animals. Our findings suggest a novel paradigm for robust coordination of tissue growth by cell-turnover, which is induced when developmental time axis is distorted. 相似文献
644.
Yukari Kakita Yukihiko Nakashima Nobufumi Ono Fumio Miake Kenji Watanabe 《Current microbiology》1996,33(6):359-363
To clarify the mechanism of Ca2+involvement in the DNA transfer through cell membrane, we studied the effects of Ca2+-chelator, Ca2+-ionophore, and Ca2+-channel blocker on the protoplast transfection of Lactobacillus casei ATCC 27092 by PL-1 phage DNA in the presence of Ca2+. Ca2+-chelators, citrate, EDTA, and dipicolinic acid, inhibited the transfection probably by compensating the effect of Ca2+. Ca2+-ionophores, A23187 and N,N,N′,N′-tetracyclohexyl-3-oxapentanediamide, which were expected to accelerate transfection by introducing
Ca2+ into cells, inhibited the transfection. This fact indicated the absence of correlation between the entry of Ca2+ and the transport of DNA into protoplasts. Verapamil, which blocks voltage-dependent Ca2+-channel besides β-adrenergic receptor, inhibited the transfection with little effect on the survival of the protoplasts.
Both flunarizine and vinpocetine, voltage-dependent Ca2+-channel blockers, did not show the selective toxicity. D-α-Aminoadipic acid, a glutamate receptor-operated Ca2+-channel blocker, had no effect. Propranolol, which blocks β-adrenergic receptor as does verapamil, inhibited the transfection
without severely damaging the protoplasts. These results suggested that a kind of receptor-operated Ca2+-channel was involved in the transport of PL-1 phage DNA into the cells and that the cell membrane might have a receptor structure
somewhat similar to the β-adrenergic receptor found in mammalian cells.
Received: 6 May 1996 / Accepted: 10 June 1996 相似文献
645.
A compound imperfect dinucleotide repeat element, [CA]4TTTGT[CT]7[CA]9AA[CA]4CCACATA[CA]3, was found approximately 10 kb 3' to the human glucokinase gene (GCK) from analysis of contiguous genomic DNA obtained from a bacteriophage lambda chromosome walk. Direct human genomic sequencing revealed the source of polymorphism to be variable numbers of CT and CA repeats. Altogether six alleles that range in length from +10 to -15 nucleotides compared to the most common (Z) allele have been identified. Alleles Z, Z + 2, and Z + 4 were present in American Blacks, Pima Indians, and Caucasians, with somewhat varied frequencies among the groups. Two alleles, Z + 10 and Z - 15, appear to be unique to American Blacks, while a Z + 6 allele was observed only in the Caucasian population studied. Observed heterozygosity of the polymorphism in the CEPH reference pedigree collection is 44% and the PIC 0.44. The polymorphism is assayed by PCR amplification and resolution of 32P-end-labeled products (ranging in length from 180 to 205 bp) on denaturing polyacrylamide sequencing gels. Using the PCR assay, the human glucokinase gene was physically localized to chromosome 7 in a panel of rodent/human somatic cell lines. Genetic analysis in CEPH pedigrees placed the dinucleotide repeat element, and thereby the human glucokinase gene, on chromosome 7p between TCRG and a RFLP locus D7S57. The glucokinase dinucleotide repeat genetic marker can now be used to assess the role of the glucokinase gene in diabetes by population association studies. In addition, this repeat marker and others flanking it on chromosome 7 can be used in linkage studies with families segregating the disorder. 相似文献
646.
Masaki Ogata Takehiko Oomori Hiroyuki Soga Yuta Ota Ari Itoh Takaji Matsutani Masanobu Nanno Ryuji Suzuki Tsunetoshi Itoh 《Cell and tissue research》2009,335(2):371-382
In our earlier work, we found that, in mice, i.p. injection of anti-CD3 monoclonal antibody activated intraepithelial lymphocytes
(iIEL), leading to DNA fragmentation in villous epithelial cells of the duodenum and jejunum within 30 min. By 2 h after injection,
nearly half of the enterocytes had detached from the villi, and DNA fragmentation could barely be detected in the remaining
villous epithelium. We hypothesized that DNA had been repaired in enterocytes in which DNA fragmentation had previously been
induced. In this study, enterocytes became negative for TUNEL staining at 60 min after anti-CD3 treatment, prior to detachment.
The remaining villous epithelial cells, after DNA fragmentation and detachment, were found to be positive for 5-bromo-2-deoxyuridine
labeling. To confirm whether fragmented DNA had been repaired in situ, we investigated the appearance and/or mobilization
of DNA-repair-related proteins. Focus formation, a typical staining pattern of repair-related proteins including phosphorylated
H2AX, phospo-ATM substrate, and Nbs1, was observed 30 min after anti-CD3 injection, with the kinetics virtually identical
to that of DNA fragmentation. The co-localization of γ-H2AX and phospo-ATM substrate was also confirmed. The disappearance
of a positive reaction for TUNEL staining in previously fragmented DNA, the appearance of representative DNA-repair-related
proteins, the coincidence of the kinetics of DNA fragmentation and this appearance of DNA-repair-related proteins, and the
co-localization of two of the repair-related proteins strongly indicated that enterocyte DNA could be repaired after it had
been fragmented in vivo. Thus, DNA fragmentation per se may not necessarily be an immediate sign of cell death.
This work was supported in part by a Grant-in-aid for Scientific Research from the Ministry of Education, Science and Culture,
Japan (16590132 to T.M., 16390045 to T.I., and 20590181 to M.O.). 相似文献
647.
648.
Leila Feiz Yukari Asakura Linyong Mao Susan R. Strickler Zhangjun Fei Margarita Rojas Alice Barkan David B. Stern 《The Plant journal : for cell and molecular biology》2021,105(3):639-648
The chloroplast RNA splicing and ribosome maturation (CRM) domain is a RNA-binding domain found in a plant-specific protein family whose characterized members play essential roles in splicing group I and group II introns in mitochondria and chloroplasts. Together, these proteins are required for splicing of the majority of the approximately 20 chloroplast introns in land plants. Here, we provide evidence from Setaria viridis and maize that an uncharacterized member of this family, CRM Family Member1 (CFM1), promotes the splicing of most of the introns that had not previously been shown to require a CRM domain protein. A Setaria mutant expressing mutated CFM1 was strongly disrupted in the splicing of three chloroplast tRNAs: trnI, trnV and trnA. Analyses by RNA gel blot and polysome association suggest that the tRNA deficiencies lead to compromised chloroplast protein synthesis and the observed whole-plant chlorotic phenotypes. Co-immunoprecipitation data demonstrate that the maize CFM1 ortholog is bound to introns whose splicing is disrupted in the cfm1 mutant. With these results, CRM domain proteins have been shown to promote the splicing of all but two of the introns found in angiosperm chloroplast genomes. 相似文献
649.
Masaki Ishida Manabu Hori Yui Ooba Masako Kinoshita Tsuyoshi Matsutani Musumi Naito Taeko Hagimoto Kuniko Miyazaki Sou Ueda Ken Miura Takashi Tominaga 《The Journal of eukaryotic microbiology》2021,68(3):e12843
In a ciliate Paramecium, the presence of water channels on the membrane of contractile vacuole has long been predicted by both morphological and physiological data, however, to date either the biochemical or the molecular biological data have not been provided. In the present study, to examine the presence of aquaporin in Paramecium, we carried out RT-PCR with degenerated primers designed based on the ParameciumDB, and an aquaporin cDNA (aquaporin 1, aqp1) with a full-length ORF encoding 251 amino acids was obtained from Paramecium multimicronucleatum by using RACE. The deduced amino acid sequence of AQP1 had NPA-NPG motifs, and the prediction of protein secondary structure by CNR5000 and hydropathy plot showed the presence of six putative transmembrane domains and five connecting loops. Phylogenetic analysis results showed that the amino acid sequence of AQP1 was close to that of the Super-aquaporin group. The AQP1-GFP fusion protein clearly demonstrated the subcellular localization of AQP1 on the contractile vacuole complex, except for the decorated spongiome membrane. The functional analyses of aqp1 were done by RNA interference-based gene silencing, using an established feeding method. The aqp1 was found to be crucial for the total fluid output of the cell, the function of contractile vacuole membranes. 相似文献